I’ve been having an issue with one of my clients using FreePBX. They recently switched and they have a single handset that is having very occasional issues answering a call. Calls are dropped into a queue, generally there’s a single member of the queue and that’s the handset in question. This issue happened when the callers were dropped straight to this handset which resulted in callers hitting voicemail so the queue was my testing/bandaid solution so the handset has more than 1 opportunity to answer. What we’re finding is that when the issue occurs the handset WILL eventually be able to answer but usually after several attempts by the queue.
The latest instances were on 5/8 and 5/9. In both cases the CDR logs on the server are showing the queue rang and there was ‘no answer’ for several 15 second tries but the call was eventually answered. In the call log on the handset it just shows the answer; no missed calls or anything before the answer.
Handset is a Grandstream GXP2170 on the latest firmware. I thought it could be a bug or problem with the handset so I swapped that out. There are about 20 other handsets and none of them have reported similar issues. All the handsets are using OVPN to the off-site FreePBX server so we shouldn’t be looking at some weird firewall or NAT issue.
Anyone have any thoughts? I’ve been googling and poking at this issue for a couple of months and not really gotten anywhere on it. I think my next test is going to be swapping to a different handset model entirely with the thought that maybe I’m dealing with some firmware bug on that model since all the other users with GXP2135s haven’t reported issues.