Phone in ring group sometimes doesn't ring

[FrankNL]

We have been using FusionPBX for a couple of months now after migrating away from FreePBX/Asterisk.
It was quite a learning curve but we have got it working the way we want it to.

However, we are faced with a very strange issue in regards to one of the phones of our secretaries.

Our inbound call flow comes in from the gateway and follows this route:
Inbound Route (General) > Time Condition (Working Hours) > Ring Group (General) > After 30 seconds timeout > Ring Group (General Fallback).

The Ring Group General contains two numbers, 412 and 413.
The fallback (used after 30 seconds) also contains these numbers but another 5 extra.
Both Ring Groups are set to the "Simultaneous" Strategy and all individual destinations have a timeout of 30 seconds.

When a call comes in to the General number, 412 + 413 rings.
If they do not answer within 30 seconds 412 + 413 rings again and also the 5 other phones. So far so good.

However.. from time to time one of the phones (413) simply does not ring while 412 works just fine.
After 30 seconds, the call falls back to the second group and again: 413 does not ring.
The phone is registered and not set to DND, so it should be able to ring.

I have tried debugging it, tried lowering the registration expiry on the phone from 1800 to 120 hoping that would be it but no luck either.

The phones of 412 and 413 are both Linksys SPA962 with a SPA932 "sidecar" running the latest firmware.
Both phones are connected to the same switch and have the same configuration (apart from Name/Extension/Password)

Version wise we are running:

• FusionPBX 4.4.6
• FreeSWITCH 1.8.5 (64bit) (1.8.4 had the same issue)
• Debian 9.9
  

Do you have any pointers how I can debug / resolve this?
Thanks!

 

[Kenny Riley]

Have you watched the sngrep logs when the call comes in and hits the ring group? You should see an sngrep INVITE attempt for each extension that is ringing in the ring group. Do you not see the INVITE being sent to extension 413?

 

[FrankNL]

Good suggestion, I'm now running "sngrep --calls" filtered with the IP of the phone as destination filter in a screen session hopefully this provides some additional insight.

 

[markjcrane]

Make sure you are using SIP with TCP. The problem you are having could be NAT related. With the SPA devices make sure you have rport enabled on the device if the phone is behind NAT.

 

[FrankNL]

We do SIP over TCP, since UDP caused some odd issues.
The connection from the phone to PBX goes via an IPsec VPN, without NAT.

In regards to NAT, the phone itself is set to the following:

 

[FrankNL]

We thought it might have been a hardware-related issue so we replaced one of the phones with a brand new one we have in stock but the issue still occurs. Are there any other things we could look in to that might help in solving this issue?

 

[pnwitguy]

Having the same issue with an extension. I know I could just reassign a new extension, but that doesn't fix the problem and really makes me nervous to switch my clients to this.

 

[finebytes]

We also have this problem is this a known issue? Any updates on it?

 

[amalkabha]

any updates, i face same problem

 

[finebytes]

we manage to fix it by making sure every client uses a different extension. For some reason if you log on using the same extension (even if it's allowed) it won't function properly in the ring group.

At least that worked for us. Making sure every extension in the ring group only logs in once