Intermittant PBX will not answer some mobiles in UK


Having an increasing issue where various PBX’s are not answering calls inbound from mobile phones.
It is intermittent, but have had a trace done on our SIP trunk Provider. Who sees an error 500 in their pcap trace

we have no reports of this happening from landline type calls only Mobiles.

Any ideas


Just guessing, when the mobile has a VoLTE connection, Asterisk rejects the call because of a codec mismatch.

If you can cause the trouble by calling from a specific mobile, at the Asterisk command prompt type
pjsip set logger on
(or sip set debug on if you are still using chan_sip)
paste the Asterisk log for a failed call at and post the link here.

If you cannot cause the trouble at will, see

for various ways to capture traffic continuously until trouble is reported.


I actually think I have a pattern match issue.

As in UK, a number can come in as +44161XXXXXXX or 0161XXXXXXX or 0044161XXXXXXX

So how do you match that syntax in one inbound route DID to allow for the 3 routes.


try _161XXXXXXX

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.