1xx = Informational Responses
SIP/2.0 100 Trying - Request is being processed
SIP/2.0 180 Ringing - Location of the called user has been determined. An incoming call signal has been issued
SIP/2.0 181 Call is Being Forwarded - The proxy server is forwarding the call to another user
SIP/2.0 182 Call is Queued - The called subscriber is temporarily unavailable; the call has been queued
SIP/2.0 183 Session Progress - Used to obtain a description of the information exchange session in advance from gateways on the path to the called user
2xx = Final Responses
SIP/2.0 200 OK - Successful completion
SIP/2.0 202 Accepted - Request accepted for processing. Used to provide information about the processing status
3xx = Redirection Messages
SIP/2.0 300 Multiple Choices - Indicates multiple SIP addresses where the called user can be found
SIP/2.0 301 Moved Permanently - The called user is no longer located at the address specified in the request
SIP/2.0 302 Moved Temporarily - The user has temporarily changed location
SIP/2.0 305 Use Proxy - The called user is not directly accessible; the incoming call must pass through a proxy server
SIP/2.0 380 Alternative Service - The requested service is unavailable, but alternative services are available
4xx = Client Error Responses (Unable to Process Request)
SIP/2.0 400 Bad Request - The request is unintelligible due to syntax errors, signaling error, likely related to hardware configuration
SIP/2.0 401 Unauthorized - Normal server response indicating that the user is not yet authorized; typically, the subscriber equipment sends a new request to the server containing the login and password
SIP/2.0 401 Expired Authorization - Registration time has expired
SIP/2.0 402 Payment Required - Payment required (reserved for future use)
SIP/2.0 403 No Such User - No such user; error in phone number, login, or password
SIP/2.0 403 User Disabled - User is disabled
SIP/2.0 403 Wrong Guess - Password error
SIP/2.0 403 Conflict - This SIP number is already in use
SIP/2.0 403 Forbidden - Subscriber is not registered
SIP/2.0 403 Empty Route Set - No gateways in the routing
SIP/2.0 403 Caller Not Registered - No such user
SIP/2.0 403 Out of Look-Ahead Retries - Exhausted node look-ahead retries
SIP/2.0 403 Invalid Phone Number - No such route/direction
SIP/2.0 403 No Money Left on RFC Account - Insufficient funds on the account to make the call
SIP/2.0 404 Not found - Called subscriber not found; no such SIP number
SIP/2.0 404 Undefined Reason - Undefined route/direction
SIP/2.0 404 Unknown user account - Login and password not found
SIP/2.0 404 Out of Order - No gateways available for routing on this direction; check the routing configuration for this direction
SIP/2.0 405 Method Not Allowed - Method not supported; may occur if a user attempts to send voicemail, etc.
SIP/2.0 406 No codecs match - Incorrect codec configuration
SIP/2.0 406 Not Acceptable - User is unavailable
SIP/2.0 407 Proxy Authentication Required - Authentication on the proxy server is required
SIP/2.0 408 Request Timeout - request processing time expired: Subscriber could not be found within the allotted time
SIP/2.0 408 Login timed out - no response received from the server to the authentication request within the allotted time
SIP/2.0 410 No Route - variant of SIP/2.0 403 Empty Route Set; no access to the resource: The resource at the specified address no longer exists
SIP/2.0 413 Request Entity Too Large - the request size is too large for the server to process
SIP/2.0 415 No Media - the call is being made using an unsupported codec
SIP/2.0 416 Unsupported Scheme - the server cannot process the request because the recipient address scheme is unknown to it
SIP/2.0 420 Bad extension - unknown extension: The server did not understand the SIP protocol extension
SIP/2.0 421 Extension Required - the request header does not specify which extension the server should apply for processing
SIP/2.0 423 Interval Too Brief - the server rejects the request because the resource validity period is too short
SIP/2.0 480 Invalid Phone Number - incorrect phone number: wrong number of digits or incorrect country or city code
SIP/2.0 480 Destination Not Found In Client Plan - the route is not included in the subscriber's tariff plan
SIP/2.0 480 Wrong DB Response - issues with the central network database
SIP/2.0 480 DB Timeout - issues with the central network database
SIP/2.0 480 Database Error - issues with the central network database
SIP/2.0 480 Codec Mismatch - codec mismatch
SIP/2.0 480 No Money Left on RFC Account - insufficient funds on the account, please contact the network administrator!!!
SIP/2.0 480 Empty Route Set - empty route, no receiving gateways available
SIP/2.0 480 No money left - insufficient funds in the account
SIP/2.0 480 Temporarily Unavailable - temporarily unavailable route, please try calling later
SIP/2.0 481 Call Leg/Transaction Does Not Exist - action not performed; normal response upon receipt of a duplicate packet
SIP/2.0 482 Loop Detected - a closed request forwarding route has been detected
SIP/2.0 483 Too Many Hops - the request passed through more proxy servers than allowed
SIP/2.0 484 Address Incomplete - a request with an incomplete address was received
SIP/2.0 485 Ambiguous - the called user's address is ambiguous
SIP/2.0 486 Busy Here - subscriber is busy
SIP/2.0 487 Request Terminated - request canceled, usually received when a call is canceled
SIP/2.0 488 Codec Mismatch - no gateways supporting the requested codec are available
SIP/2.0 488 Private IP Address - RTP media address from RFC1918 networks
SIP/2.0 491 Request Pending - the request arrived while the server was still processing another request related to the same dialog
SIP/2.0 493 Undeciperable - the server is unable to select a decryption key: impossible to decode the S/MIME message body
SIP/2.0 499 Codec Mismatch - codec missing
5xx = server errors
SIP/2.0 500 Internal Server Error - internal server error
SIP/2.0 500 DB Timeout - no response from the database
SIP/2.0 500 Database Error - same as above, but occurring at a different time
SIP/2.0 500 Wrong DB Response - incorrect database response, rare error
SIP/2.0 500 Undefined Reason - undefined reason
SIP/2.0 500 account has been moved to a remote system - account has been migrated to a remote system (literal translation)
SIP/2.0 501 Method Not Supported Here - the server does not implement any of the functions required to service the request: the SIP request method is not supported
SIP/2.0 502 Bad Gateway - a server acting as a gateway or proxy server received an invalid response from the server to which it forwarded the request
SIP/2.0 503 Service Unavailable - the server is currently unable to service the call due to overload or maintenance
SIP/2.0 504 Server time-out - the server did not receive a response within the specified time interval from the server it contacted to complete the call
SIP/2.0 505 SIP Version not supported - the version is not supported: the server does not support this version of the SIP protocol
SIP/2.0 513 Message too big - the server is unable to process the request due to the large message length
6xx = global error
SIP/2.0 600 Busy everywhere - the called user is busy and does not wish to accept the call at this time
SIP/2.0 603 Decline - the called user does not wish to accept incoming calls, without specifying the reason for refusal
SIP/2.0 604 Does Not Exist Anywhere - the called user does not exist
SIP/2.0 606 Not Acceptable - the connection to the server was established, but individual parameters such as the type of requested information, bandwidth, and addressing type are not available