This document lists the error codes that Dotcom-Monitor can return, organized by error type. Each section covers one error type and contains a table of error codes with their descriptions. Use this reference to identify the cause of an error returned by a monitoring task.

Validation

Error Code	Description
100	Invalid URL.
101	Invalid Host.
102	The file size exceeds the allowed limit.
103	One or more files were not found.
104	Can’t process this RecordType.
105	Invalid header format.
106	Sorry, Internal Error.
107	Response size is greater than max. size.
108	Max. redirect attempts arrived.
109	Script compilation error.
110	DNS Timeout.
111	Minimum threshold is reached.
112	Maximum threshold is reached.
113	Max. authorization attempts reached.
115	Invalid Port.
117	Invalid response code.
120	Element not found.
121	Assert failed.
122	Unknown error.
123	The operation was canceled.
124	Script execution timeout has expired.
125	Custom script error.
126	File Download did not start.
127	File Download did not finish.
128	Response status code does not match expected response codes.
129	Security check failed.
300	Duration exceeded specified threshold.
350	Test message not found.
351	Mail message timeout expired.
360	Wrong result.
400	Keyword not found.
401	Syntax error in keyword expression.
402	Syntax error in DNS expression(s).
450	IP found.
470	Frame Rate greater than permissible max.
471	Frame Rate is less than permissible min.
480	Hit count is greater than permissible max.
481	Hit count is less than permissible min.
482	Average time greater than permissible max.
490	Navigating logic has been changed since Device creation.
491	Image not found.
492	NetworkResponseModifier custom error.
700	Credential failed to authenticate.
701	No suitable credential is found to authenticate the request against the received authentication challenge in 401/407 response.

Runtime

Error Code	Description
100	Runtime exception.
101	Script execution error.
102	Network error.
103	Parameter calculation error.
104	Cookie calculation error.
105	Header calculation error.
106	URL calculation error.
107	Before-execute script execution error.
108	Post-execute script execution error.
115	Counter value is not available.
116	Counter initialization failure.
117	Remote computer connection error.
120	Content size is too big for regular expression validation.
122	Onsite Proxy Agent cannot connect to Load Injector.
130	The request was aborted.
131	Script execution was aborted.
132	Runtime execution timeout.
133	The request was forcibly closed by proxy agent.
140	Plugin is not supported.
141	Error from browser console.
142	The request was aborted by CORS policy.
143	The request was blocked by firewall.
200	Unknown Error.

Certificate

Error Code	Description
41	0xC00D0029: The network connection has failed.
100	Certificate cannot be validated.
101	Certificate Date validation fault.
102	Certificate Revocation validation fault.
103	Certificate Authority validation fault.
104	Certificate CN validation fault.
105	Certificate Usage validation fault.
106	Certificate will expire soon.

Cryptographic

Error Code	Description
100	Authenticate failed.
101	Can not find supported authenticate algorithm.
102	Secure protocol negotiation failed.

TCP

Error Code	Description
1234	No service is operating at the destination network endpoint on the remote system.
1235	The request was aborted
10013	An attempt was made to access a socket in a way forbidden by its access permissions
10049	The requested address is not valid in its context.
10051	A socket operation was attempted to an unreachable network.
10052	The connection has been broken due to keep-alive activity detecting a failure while the operation was in progress.
10053	An established connection was aborted by the software in your host machine
10054	An existing connection was forcibly closed by the remote host.
10060	A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
10061	No connection could be made because the target machine actively refused it.
10065	A socket operation was attempted to an unreachable host.
12500	An unexpected error occurred on a send.
12501	An unexpected error occurred on a recive.
12502	Pipeline failure.
12503	The name resolver service could not resolve the proxy host name.
12504	This request was not permitted by the proxy.
12505	No data received.
12506	Destination unreachable.
12507	Connection refused.

DNS

Error Code	Description
100	Unknown DNS error.
101	Format error – The name server was unable to interpret the query.
102	Server failure – The name server was unable to process this query due to a problem with the name server.
103	Name Error – Meaningful only for responses from an authoritative name server, this code signifies that the domain name referenced in the query does not exist.
104	Not Implemented – The name server does not support the requested kind of query.
105	Refused – The name server refuses to perform the specified operation for policy reasons.
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.
12007	The host name could not be resolved.

UDP

Error Code	Description
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.
1234	No service is operating at the destination network endpoint on the remote system.
10049	The requested address is not valid in its context
10051	A socket operation was attempted to an unreachable network
10052	The connection has been broken due to keep-alive activity detecting a failure while the operation was in progress
10054	An existing connection was forcibly closed by the remote host
10060	A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond
10061	No connection could be made because the target machine actively refused it
10065	A socket operation was attempted to an unreachable host.
12500	An unexpected error occurred on a send.
12501	An unexpected error occurred on a recive.
12503	The name resolver service could not resolve the proxy host name.
12504	This request was not permitted by the proxy.
12505	No data received.
12506	Destination unreachable.
12507	Connection refused.

HTTP

Additionally, our glossary for HTTP status codes can explain references of HTTP Error Codes further.

Error Code	Description
0	Unknown error.
400	Bad Request. The request cannot be fulfilled due to bad syntax.
401	Unauthorized. Authentication is possible but has failed or not yet been provided.
402	Payment Required.
403	Forbidden. The request was a legal request, but the server is refusing to respond to it.
404	Not Found. The requested resource could not be found.
405	Method Not Allowed. A request was made of a resource using a request method not supported by that resource.
406	Not Acceptable. The requested resource is only capable of generating content not acceptable according to the Accept headers sent in the request.
407	Proxy Authentication Required.
408	Request Timeout. The server timed out waiting for the request.
409	Conflict. Indicates that the request could not be processed because of conflict in the request, such as an edit conflict.
410	Gone: Indicates that the resource requested is no longer available and will not be available again.
411	Length Required. The request did not specify the length of its content, which is required by the requested resource.
412	Precondition Failed. The server does not meet one of the preconditions that the requester put on the request.
413	Request Entity Too Large. The request is larger than the server is willing or able to process.
414	Request-URI Too Long. The URI provided was too long for the server to process.
415	Unsupported Media Type. The request entity has a media type which the server or resource does not support.
416	Requested Range Not Satisfiable. The client has asked for a portion of the file, but the server cannot supply that portion.
417	Expectation Failed. The server cannot meet the requirements of the Expect request-header field.
422	Unprocessable Entity. The request was well-formed but was unable to be followed due to semantic errors.
423	Locked: The resource that is being accessed is locked.
424	Failed Dependency. The request failed due to failure of a previous request.
425	Unordered Collection.
426	Upgrade Required. The client should switch to a different protocol such as TLS/1.0.
429	Too Many Requests
449	Retry With: The request should be retried after performing the appropriate action.
450	Blocked by Windows Parental Controls. This error is given when Windows Parental Controls are turned on and are blocking access to the given webpage.
500	Internal Server Error. A generic error message, given when no more specific message is suitable.
501	Not Implemented. The server either does not recognise the request method, or it lacks the ability to fulfill the request.
502	Bad Gateway. The server was acting as a gateway or proxy and received an invalid response from the upstream server.
503	Service Unavailable. The server is currently unavailable (because it is overloaded or down for maintenance).
504	Gateway Timeout. The server was acting as a gateway or proxy and did not receive a timely response from the upstream server.
505	HTTP Version Not Supported. The server does not support the HTTP protocol version used in the request.
506	Variant Also Negotiates. Transparent content negotiation for the request results in a circular reference.
507	Insufficient Storage.
509	Bandwidth Limit Exceeded (Apache bw/limited extension).
510	Not Extended. Further extensions to the request are required for the server to fulfill it.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1006	Server protocol violation.
1007	The request was not permitted by the cache policy. In general, this occurs when a request is not cacheable and the effective policy prohibits sending the request to the server.
1009	Operation timeout.
2000	The associated condition is not a result of an error.
2001	The endpoint detected an unspecific protocol error.
2002	The endpoint encountered an unexpected internal error.
2007	The endpoint refused the stream prior to performing any application processing.
2008	Used by the endpoint to indicate that the stream is no longer needed.
2011	The endpoint detected that its peer is exhibiting a behavior that might be generating excessive load.
2013	The endpoint requires that HTTP/1.1 be used instead of HTTP/2.
3001	An internal implementation error occurred.
3006	The connection timed out waiting for a response from the peer.
3010	The connection timed out from inactivity.
10060	The operation timed out
12002	The operation timed out.
12029	A connection with the server could not be established.
12030	The connection with the server was terminated abnormally.
12031	The connection with the server was reset.
12152	The server returned an invalid or unrecognized response.

FTP

Error Code	Description
421	Service not available, closing control connection. This may be a reply to any command if the service knows it must shut down.
425	Can’t open data connection.
426	Connection closed; transfer aborted.
431	Unknown temporary authentication or accounting error.
450	Requested file action not taken.
451	Requested action aborted. Local error in processin.
500	Syntax error, command unrecognized. This may include errors such as command line too long.
501	Syntax error in parameters or arguments.
502	Command not implemented.
503	Bad sequence of commands.
521	Unknown permanent connection error.
530	Not logged in.
532	Need account for storing files.
534	Unknown permanent authentication or accounting error.
550	Requested action not taken. File unavailable.
555	Unknown permanent file system error.
560	Unknown permanent error.
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1008	No server request for data channel creation.
1009	Operation timeout.

SFTP

Error Code	Description
100-101	Unknown Error.
102	Recursive directory use.
103	Bad Directory.
104	Bad remote Directory.
105	No such directory.
106	Error openning communication channel.
107	Inputstream is closed.
108	Bad response status.
109	Connection is down.
110	Channel is not opened.
111	Failed to send subsystem request.
112	Bad remote port.
113	Syntax error.
114	Unknown Error.
118	Accessible fault.
119	Verify fault.
120	Invalid data.
121	Invalid protocol.
122	Faile to resume.
123	Not Supported.
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.

SMTP

Error Code	Description
400-401	Unknown temporary syntax error.
404	Unknown temporary syntax error.
420	Unknown temporary connection error.
421	Service not available, closing transmission channel.
422	Unknown temporary connection error.
432	Unknown temporary error.
434	Unknown temporary error.
435	Unknown temporary error.
440	Unknown temporary error.
450	Requested mail action not taken. Mailbox unavailable.
451	Requested action aborted. Local error in processing.
452	Requested action not taken. Insufficient system storage.
454	Unknown temporary error.
475-476	Unknown temporary error.
500	Syntax error, command unrecognized.
501	Syntax error in parameters or arguments.
502	Command not implemented.
503	Bad sequence of commands.
504	Command parameter not implemented.
513	Unknown permanent information error.
521-522	Unknown permanent connection error.
530	Access denied.
534	Unknown permanent error.
535	Unknown permanent error.
542	Unknown permanent error.
550	Requested action not taken: mailbox unavailable.
551	User not local.
552	Requested mail action aborted: exceeded storage allocation.
553	Requested action not taken: mailbox name not allowed.
554	Transaction failed.
555	MAIL FROM/RCPT TO parameters not recognized or not implemented.
556	Unknown permanent error.
571	Unknown permanent error.
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.
1010	Email address in Suppress list.
1011	The specified string is not in the form required for an email address.

POP3

Error Code	Description
400	Error on command CAPA.
401	Error on command AUTH.
402	Error on command STLS.
403	Error on command USER.
404	Error on command PASS.
405	Error on command STAT.
406	Error on command TOP.
407	Error on command DELE.
408	Error on command QUIT.
409	Server greeting error.
410	Error on command RETR.
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.

IMAP

Error Code	Description
400	Error on command CAPABILITY.
401	Error on command AUTHENTICATE.
402	Error on command LOGIN.
403	Error on command STARTTLS.
404	Error on command SELECT INBOX.
405	Error on command UID SEARCH.
406	Error on command UID STORE.
407	Error on command LOGOUT.
408	Server greeting error.
409	Error on command EXPUNGE.
410	Error on command FETCH.
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.

ICMP

Error Code	Description
402	Network that contains the destination computer is not reachable.
403	Destination computer is not reachable.
404	Contact with the destination computer is administratively prohibited.
405	Destination Port Unreachable.
406	Insufficient network resources.
407	Invalid option.
408	Hardware error.
409	Packet containing the request is larger than the maximum transmission unit (MTU) of a node (router or gateway) located between the source and destination.
410	Request timeout.
412	There is no valid route between the source and destination computers.
413	Time to Live (TTL) value reached zero, causing the forwarding node (router or gateway) to discard the packet.
414	Packet was divided into fragments for transmission and all of the fragments were not received within the time allotted for reassembly.
415	Node (router or gateway) encountered problems while processing the packet header.
416	Packet was discarded.
418	Destination IP address cannot receive ICMP echo requests or should never appear in the destination address field of any IP datagram.
440	Destination Unreachable.
441	Time to Live (TTL) value reached zero, causing the forwarding node (router or gateway) to discard the packet.
442	Bad Header.
443	Unrecognized Next Header.
444	ICMP protocol error.
445	Source address and destination address that are specified in an ICMP echo message are not in the same scope.
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.

ICMP V6

Error Code	Description
402	Network that contains the destination computer is not reachable.
403	Destination computer is not reachable.
404	Contact with the destination computer is administratively prohibited.
405	Destination Port Unreachable.
406	Insufficient network resources.
407	Invalid option.
408	Hardware error.
409	Packet containing the request is larger than the maximum transmission unit (MTU) of a node (router or gateway) located between the source and destination.
410	Request timeout.
412	There is no valid route between the source and destination computers.
413	Time to Live (TTL) value reached zero, causing the forwarding node (router or gateway) to discard the packet.
414	Packet was divided into fragments for transmission and all of the fragments were not received within the time allotted for reassembly.
415	Node (router or gateway) encountered problems while processing the packet header.
416	Packet was discarded.
418	Destination IP address cannot receive ICMP echo requests or should never appear in the destination address field of any IP datagram.
440	Destination Unreachable.
441	Time to Live (TTL) value reached zero, causing the forwarding node (router or gateway) to discard the packet.
442	Bad Header.
443	Unrecognized Next Header.
444	ICMP protocol error.
445	Source address and destination address that are specified in an ICMP echo message are not in the same scope.
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.
1231-1232	The network location cannot be reached. For information about network troubleshooting, see Windows Help
10051	A socket operation was attempted to an unreachable network

DNSBL

Error Code	Description
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.

Media

Error Code	Description
6	Unable to establish a connection to the server. Native error code: ‘0xC00D0006’.
19	The server, a computer set up to offer multimedia content to other computers, could not handle your request for multimedia content in a timely manner.  Please try again later. Native error code: ‘0xC00D0013’.
26	The system cannot find the file specified. Native error code: ‘0xC00D001A’.
38	The specified protocol is not recognized. Be sure that the file name and syntax, such as slashes, are correct for the protocol. Native error code: ‘0xC00D0026’.
41	The network connection has failed.
51	There is no stream available. Native error code: ‘0xC00D0033’.
53	The specified server could not be found. Native error code: ‘0xC00D0035’.
64	The specified network name is no longer available
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.
5101	The specified origin server cannot be found. Native error code: ‘0xC00D13ED’.
10051	A socket operation was attempted to an unreachable network
12000	The specified protocol is not supported. Native error code: ‘0xC00D2EE0’.
12002	The server encountered an unexpected condition which prevented it from fulfilling the request. Native error code: ‘0xC00D2EE2’.
12004	The proxy experienced an error while attempting to contact the media server. Native error code: ‘0xC00D2EE4’.
12006	The server is currently unable to handle the request due to a temporary overloading or maintenance of the server. Native error code: ‘0xC00D2EE6’.
12007	The server is refusing to fulfill the requested operation. Native error code: ‘0xC00D2EE7’.
12026	The MMS protocol is not supported. Please use HTTP or RTSP to connect to the Windows Media stream. Native error code: ‘0xC00D2EFA’.
12038	It was not possible to establish a connection to the media server in a timely manner. The media server may be down for maintenance, or it may be necessary to use a proxy server to access this media server. Native error code: ‘0xC00D2F06’.
12039	It was not possible to establish a connection to the proxy server in a timely manner. Please check your proxy server configuration. Native error code: ‘0xC00D2F07’.
65537	Sample rate is invalid.
65538	Input stream information is invalid.
65539	Connection failed.
65546	Multimedia stream can not be found.

SIP

Error Code	Description
400	Bad Request.
401	Unauthorized (Used only by registrars or user agents. Proxies should use proxy authorization 407).
402	Payment Required (Reserved for future use).
403	Forbidden.
404	Not Found (User not found).
405	Method Not Allowed.
406	Not Acceptable.
407	Proxy Authentication Required.
408	Request Timeout (Couldn’t find the user in time).
410	Gone (The user existed once, but is not available here any more.).
415	Unsupported Media Type.
477	Unknown client error.
478	Unknown client error.
480	Temporarily Unavailable.
482	Loop Detected.
483	Too Many Hops.
484	Address Incomplete.
485	The callee address provided in the request was ambiguous.
487	Request Terminated.
488	Not Acceptable Here.
491	Request Pending.
500	Server Internal Error.
501	Not Implemented: The SIP request method is not implemented here.
502	Bad Gateway.
503	Service Unavailable.
504	Server Time-out.
600	Busy Everywhere.
603	The callee’s machine was successfully contacted but the user explicily does not wish to or cannot participate.
604	Does Not Exist Anywhere.
606	Not Acceptable.
620	Unknown global error.
1000	Unknown error.
1001	Incorrect replay syntax.
1002	Receive timeout.
1003	A message was received that exceeded the specified limit when sending a request or receiving a response from the server.
1004	An unexpected end symbols.
1005	An unexpected protocol error occurred.
1009	Operation timeout.
10049	The requested address is not valid in its context.

ActiveSync

Error Code	Description
399	Server does not support necessary command’s set.
400	Infinite redirection loop.
401	Invalid Policy Key.
402	Inbox not found in hierarchy.
403	Empty sync request was returned.
404	Invalid options response.
405	Error during Provision command execution.
406	Error during SendMail command execution.
407	Error during FolderSync command execution.
408-409	Error during Sync command execution.