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SIP Error Codes & SIP Trunk Troubleshooting

SIP Error Codes & SIP Trunk Troubleshooting

Outbound calls error with "all circuits busy" or "congestion":

This is the default configuration of Asterisk regardless of the actual error generated (which is infuriating when you are trying to diagnose the real problem) unless PBX is updated to send back the real error rather than the changed error. This error most commonly occurs when the call is not authenticating properly, at which point check the above in the SIP trunk configuration (If Asterisk, swap username= for defaultuser= to see if this solves the issue. Just because a trunk is showing as registered does not mean it will authenticate correctly.

Outbound calls fail with SIP error 488 (Not Accepted Here) or I-SUP errors 58 (bearer capability not available) or 88 (incompatible destination):

Check the codecs allowed in the SIP trunk configuration above, VoiceHost only supports: alaw, ulaw, gsm
If a codec is defined in Asterisk that is not one of the above, or is offering a differing sample rate or interval rate (e.g. 8000/20i - 8000Hz at 20ms) cannot interwork with 16000/30i - 16000Hz at 30ms) the call will fail and the codecs in the SIP trunk configuration need to be aligned to use one of the above codecs.

Inbound calls fail with SIP error 408 (Request Timeout):

Check the inbound number is mapped in the system correctly, if necessary the SIP trunk on the portal can be configured to strip the plus, e.g. if Asterisk is configured to use plus somewhere else. Check the trunk is registered. Ascertain how long the 408 error took to come back if it was immediate the trunk is usually unregistered if it took a few seconds the number is usually not mapped correctly.

Calls fail with SIP error 503, I-SUP errors 34 or 38:

If our platform replies back with 503 it usually means the gateway trying to process the call can't due to "issues", or the customer has hit their Calls-Per-Second (CPS) limit and is sending too many calls at once. Sometimes the error is passed back from IP Exchange through VoiceHost to the customer's system, at which point the call will usually hunt to another route to try and place the call.

Cause code (ISUP)SIP EquivalentDefinition
1404 Not FoundUnallocated (unassigned) number
2404 Not foundno route to network
3404 Not foundno route to destination
16BYE or CANCEL (*)normal call clearing
17486 Busy hereuser busy
18408 Request Timeoutno user responding
19480 Temporarily unavailableno answer from the user
20480 Temporarily unavailablesubscriber absent
21403 Forbidden (+)call rejected
22410 Gonenumber changed (w/o diagnostic)
22301 Moved Permanentlynumber changed (w/ diagnostic)
23410 Goneredirection to new destination
26404 Not Found (=)non-selected user clearing
27502 Bad Gatewaydestination out of order
28484 Address incompleteaddress incomplete
29501 Not implementedfacility rejected
31480 Temporarily unavailablenormal unspecified
34503 Service unavailableno circuit available
38503 Service unavailablenetwork out of order
41503 Service unavailabletemporary failure
42503 Service unavailableswitching equipment congestion
47503 Service unavailableresource unavailable
55403 Forbiddenincoming calls barred within CUG
57403 Forbiddenbearer capability not authorized
58503 Service unavailablebearer capability not presently
65488 Not Acceptable Herebearer capability not implemented
70488 Not Acceptable Hereonly restricted digital avail
79501 Not implementedservice or option not implemented
87403 Forbiddenuser not member of CUG
88503 Service unavailableincompatible destination
102504 Gateway timeoutrecovery of timer expiry
111500 Server internal errorprotocol error
127500 Server internal errorinterworking unspecified