No audio of caller on recipient end - happens randomly

[cmdr.adama]

Hey guys,

Currently trying to troubleshoot a fairly random issue with our 3CX PBX.
When someone makes a call extension to extension, extension to external, or external to extension, there is a random chance that the recipient of the call will just get dead silence.

Some info about our PBX
3CX Version: Standard Annual - 16.0.8.9
Server OS: Debian 9
Is the 3CX Server Hosted and where: Yes, Google Cloud
Provisioning Method: Direct SIP STUN
Has the Firewall Checker passed: YES
Are custom Phone Templates being used: NO

Steps to reproduce:
Internal:
Step 1. Caller dials another 3CX Extension or external number
Step 2. Recipient picks up and starts to talk.
Step 3. Caller can not be heard by the recipient.

External:
Step 1. External caller dials our DID.
Step 2. Recipient picks up and starts to talk
Step 3. Caller can not be heard by the recipient.

I have also replicated this with the Echo Test (*777)

Interestingly I decided to see if there were any Debian packages needing to be updated and after doing some further testing, this seems to have resolved the issue.
These were:
python2.7-minimal:amd64 (2.7.13-2+deb9u4, 2.7.13-2+deb9u5),
libpython2.7:amd64 (2.7.13-2+deb9u4, 2.7.13-2+deb9u5),
python2.7:amd64 (2.7.13-2+deb9u4, 2.7.13-2+deb9u5),
google-cloud-packages-archive-keyring:amd64 (1.2-350029030, 1.2-369250246),
google-compute-engine-oslogin:amd64 (1:20200925.00-g1+deb9, 1:20210122.00-g1+deb9),
google-cloud-sdk:amd64 (321.0.0-0, 336.0.0-0),
libpython2.7-minimal:amd64 (2.7.13-2+deb9u4, 2.7.13-2+deb9u5),
libpython2.7-stdlib:amd64 (2.7.13-2+deb9u4, 2.7.13-2+deb9u5)

Is it possible that this issue was being caused by the previous update for python?
Also why is 3cx still using python 2.7...

 

[VasilisV_3CX]

Hi @cmdr.adama,

Have you had a look at our STUN troubleshooting guide which may be able to point you in the right direction?

Does this happen over two new extensions using the Web Client?

Is this specific 1 or a number of IP phones or is it ALL IP phones?

 

[cmdr.adama]

Hey @VasilisP_3CX, thanks for the quick reply.

I haven't gone through that guide in the past. For the most part this is what is in place aside from the unique SIP ports and Static IP's for each phone.

It doesn't matter whether it's a desk phone, Windows application, Android app or iOS app and the issue occurs internally as well as on 4G or on my home network. Everything seemed to be affected.

 

[VasilisV_3CX]

Hi @cmdr.adama,

This sounds quite suspicious and very abnormal. It sounds like something a 3CX Partner would need to investigate. You can find a 3CX Partner here.