Solved Unable to answer ring group call, backup phone rings also and can answer - intermittent

[Samson]

My previous thread was closed.
https://www.3cx.com/community/threa...rings-also-and-can-answer-intermittent.68370/

Here is my original question...

Hi there,
I've scoured these forums for somebody with a similar issue as me, but I can't seem to find anything the same, so here goes...

I've got a local 3CX windows installation 15.5.15502. (Now 16.0.676) Upgraded to v16 and issue remains.
I'd say 90% of the time it all works as expected, all desk phones ring in the ring group and can be answered or it goes to VM. Great!
However that other 10% is the doozy.
The desk phones will all ring and appear normal (displaying the caller id of the person calling), but after you lift the receiver the call ends immediately. This happens with all extensions.
However, with my VoIP provider, Engin (Australia), they have a reach me feature, so in case I lose internet at the office a backup mobile/cell phone can take the call.
And when the above issue occurs, the mobile/cell phone rings also - and the call can be answered from there.
Answering the call on the mobile/cell does not stop all the desk phones ringing. They will eventually time out, or everyone picks up their phones and hangs up again.
The internet has not gone down when this happens.

I have another office with a pretty much identical - as far as I can tell, 3CX installation in a different location, same ISP, same VoIP provider, same SPA942 or 504G handsets but this issue does not occur.

I've increased my logging to medium and caught and instance when it occurs, see below.

If anyone has any insight to this unbelievably hair pulling error, I would greatly appreciate it!! Thanks!

Notes: I have since upgraded to v16 and the issue remains. The issue is the same with PC apps. I have disabled IPv6 on my modem, and unchecked bind in network settings.

 

[Zol]

they have a reach me feature, so in case I lose internet at the office a backup mobile/cell phone can take the call.

It looks like you're loosing the SIP trunk registration.
If the trunk is authenticated (no IP based) you should see that in the SIP Trunks menu.
Check if 3CX sent a new registration to your provider.

 

[JohnS_3CX]

Hi Samson,

Please follow this guideline here and provide as accurate info as possible so we can understand the case better https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

 

[Samson]

Thanks for the reply Zol.
Registration OK is from two days ago, however the issue has been occurring again today.

 

[Samson]

FYI this has been resolved.
I installed a different modem and the issue has stopped.
All firewall rules were the same on both. So unfortunately I'm unsure of the underlying issue.