Incoming calls are disconnected in 1-2 minutes

[invia1]

Hello everyone,
I want to give some info about my 3cx system.

We have 3cx v15.5 on windows 10 and Dinstar dag-1000 fxo gateway device and we have static ip address. We also have 3 branch office and they have a Fanvil X3S model phone. Our service provider brought 5 phone lines via fiber optics modem.

We had to use the 6060 port in 3cx because the 5060 port uses the service provider in the modem.

when I come to the point of my problem, while the customer calls from outside, the line is cut off automatically after 15-30 seconds or 2-3 minutes. IPhone, android, and windows softphone do not have any problems when we speak with them, this problem occurs only on remote extension fanvil phones. In order to make a solution, I made the voice transmission TCP on the fanvil phones and I wrote the static IP address of the 3cx server in fanvil phone account. Besides, I also checked and test it on 3cx firewall controller and all ports are green/ok. I tried to listen SIP ports on Wareshark app but it does not show any problems when the line is cut off

I attached some screenshots
Can anyone help me about this problem?

 

[eddv123]

Hi Inva1,

If these calls are SIP Trunk calls almost definitely this is a firewall problem, you either have SIP ALG enabled on the firewall or your public IP may of changed.

I see reference in your post to FXO trunks but not who your SIP trunking provider is although referencing several points which suggest you are using one.

If your issue is purely FXO disregard my last and ignore the Firewall checker and port forwarding etc.

 

[YiannisH_3CX]

Hello @invia1

Also are the phones provisioned? Did you manually provision them or are they provisioned using STUN? Have you tried using an SBC as a test? Make sure that the phones are running the latest supported firmware from 3CX and the default templates.
https://www.3cx.com/support/phone-firmwares/

 

[PTG]

With the drop of calls after 30 sec's, it sounds like a RTP timeout issue, i.e. not getting ACK packet back and usually related to NAT / Firewall issues.
Also make sure you have latest firmware and templates fo the phones from 3CX