I’ve got a strange situation with my outgoing calls. Just last week, users are reporting that some external phone numbers they dial will ring and then it sounds like on the far end is picking up but they dont hear anything. No audio or beeps from the far end just dead silent but the call is still active. So far it is only happening to about 4-5 different phone numbers.
I contacted our SIP provider (Voyant) and they told me they are seeing the call go through to the far end and picked up but they are seeing ‘481 Call Leg extension does not exist’. Voyant believes its something to do with FreePBX. I’m not a VoIP person and have no clue where to begin and troubleshoot this problem. As I mentioned, we can make all other calls outgoing without a problem just specific to 4-5 phone numbers. Any help is greatly appreciated.
The other strange issue is that the problem goes away for several days and then it comes back. For example, so far today we can make calls to those same phone numbers without a problem. I was planning to do a tcpdump today but cant really do it if its working again.
I’m gonna go out on a limb and guess it’s a Codec error, or some other similar issue. The fact that the problem comes and goes leads me (typically) in the direction of a NAT configuration/timeout error, but codec problems, especially if you’re using any of the “cool kid” codecs could cause this as well.