Solved Issues with adding a second trunk

[veteranITguy]

Recently, one of my clients have been experiencing issues with their calls. One-way audio, dropped calls, no audio, etc. After working with both the SIP provider (SIP.US) and 3CX, it was decided that we would move them to a new SIP provider. I setup a second trunk using Twilio to test before we move everyone over. However, I've been unable to get the Twilio trunk to work. In 3CX, the trunk test says everything is fine, but I'm unable to make calls inbound calls to the trunk. Outbound works mostly but will fail every so often. In Twilio, I can see the call logs saying that there is a communication error.



I followed everything on the setup instruction. Being Twilio, it was all automatic. I've tried everything I can to get this second trunk to work correctly. 3CX is currently running Version 20.0 Update 8 (Build 1121 Release) but was in-placed upgraded from v18. Another thing of note, this has been in-placed upgraded since they got the system, we are unsure what they started at as we inherited the system but believe it was v14. My next idea is to rebuild the server entirely and restore from a backup. Any additional insights or help would be greatly appreciated.

One final note, using our in-house test system, we were able to successfully setup a Twilio trunk as a second trunk and have experienced no issues with that, so I don't believe it was setup incorrectly.

 

[BrunoI_3CX]

As a first step, please navigate to Admin > Dashboard > Troubleshooting > Firewall and ensure that the Firewall Test is performed with all tests showing green indicators.

If this is something you have already confirmed, another suggestion would be to start a packet capture while the issue occurs to verify whether the RTP packets are reaching the system accordingly.

Do you find any issue while performing internal calls between users? Or are calls heard accordingly in that scenario?

 

[veteranITguy]

We have ran the firewall checker and it is good. We are also done troubleshooting the SIP.US trunk. There have been issues with that for a while with no resolution and they are moving away.

Right now, we are trying to get the new trunk to work. We currently only have two DIDs for the Twilio trunk, one for the trunk and another for testing. I can see about getting another one for testing internal calls. As for the RTP packets, according to Twilio, the packets are being sent, but no response is sent. I checked everywhere I could for the packets, but nothing was logged. I can conduct a new test when able and run a packet capture. I confirmed that everything is setup on both sides correctly according to the documentation that I can find.

 

[veteranITguy]

Okay, I have a packet capture of us trying to call the DID on the Twilio trunk. Would you like it in a dm?

 

[YiannisH_3CX]

You can send me a dm and share the packet capture. Also use this guide for reference and make sure that everything is in place on Twilio's end.

 

[veteranITguy]

Okay, dm sent. I also used that guide and Twilio's documentation to check. Everything seems to be setup correctly.

 

[veteranITguy]

I was able to figure it out. Unbeknownst to me, a custom firewall rule was put in place in Lightsail that was blocking the traffic. We should be good now. Thank you for the assistance.