Calls drop when session-expires is reached

[joseror]

Hi!
I'm currently using 3CX with an unsupported provider as none of the providers in my country are supported. I've been having issues since day 1 with calls dropping at the 5 minute mark. I contacted my VoIP support, but they told me calls are registered as being terminated from the origin. When using my SIP without 3cx via Zoiper, calls don't drop. Firewall checker came back okay. While going through the logs I noticed that the session-expires is set to 1800 which is exactly the time it takes before a call drops.
I changed the logs to verbose and noticed that there is usually a message sent with a tag from 3CX to origin and right after that the source sends a BYE disconnecting the call.
I've tried all sorts of troubleshooting I can think of without success.
Running on a Google Cloud VM.

Product	Standard Annual
Version Number	18.0 (Build 312)

 

[Alphabetic]

Have you got supports reinvites enabled on your sip trunk?

 

[joseror]

Yes, I got supports reinvites enabled.
I see in the logs that 3CX sends this message:

SendMsg from <sip:Number@IPort>;tag=382bd711 to <siphonenumber@IPort>;tag=atc-59ccef21-49d8fed1

and right after that message is sent the caller responds with a BYE:

07/14/2023 10:38:12 AM - L:3.1[Line:10000<<NUMBER] Sending: OnSendResp Send 200/BYE from 0.0.0.0:0 tid=366993ec3367e98641b03 Call-ID=553fbccd-a5f46c9-49a41fdb-a7044a1f@IP:SIP/2.0 200 OKVia: SIP/2.0/UDP IPORT;branch=z9hG4bK366993ec3367e98641b03Contact: <sip:NUMBER@IPORT>To: <sip:NUMBER@IPORT>;tag=382bd711From: <sip:NUMBER@IPORT>;tag=atc-59ccef21-49d8fed1Call-ID: 553fbccd-a5f46c9-49a41fdb-a7044a1f@IPCSeq: 467508617 BYEContent-Length: 0

 

[TheodorosG_3CX]

I would suggest that you disable the Re-invites on your sip trunk and check.

 

[joseror]

It was initially disabled, I tried to enable it since it was mentioned here, but same result with both.

 

[TheodorosG_3CX]

The 5 minutes is very specific here. This happens no matter if you are using 3CX Clients or ip phones?
Note that this option should be enabled and in case you have modified the sip trunk default parameters ensure to revert back to the default.

 

[joseror]

I don't use any IP phones, just the 3CX app on PC and iPhone. Calls drop exactly at 5 min every time on all apps.

 

[TheodorosG_3CX]

The session timer is 1800 sec which can explain why the call is terminated, however this requires further investigation.
I would suggest that you create a ticket to the 3CX Support to proceed from there.

 

[leejor]

1800 seconds = 30 minutes, not 5 minutes.

 

[joseror]

Yes. All I can see is a tagged message being sent from 3CX to the caller at the 5 minute mark and then the caller sends a BYE afterwards.

 

[TheodorosG_3CX]

Just to clarify the BYE is coming from the provider side?

 

[joseror]

The bye is from the incoming provider, but this happens with all incoming calls regardless of provider.

 

[joseror]

Turns out that it was the anti-hacking feature blocking the call after 5 minutes. I increased the number of allowed packets and the call was able to go past 5 min. Will try to get the IPs from my trunk provider so I can whitelist them and return the packets to their original amts.