No audio on incoming and outgoing external calls

[MontEnt]

We just migrated to 3CX hosting and all internal calls, web meeting, etc. features are working, however, when making or receiving calls with the external number, the receiving end rings, but has no sound when answered.

3CX Version: Professional Annual 18.0 Update 6 (Build 908)
Server OS: Unknown, 3CX Server Hosted
Has the Firewall Checker passed: Shows as passed
We have IP Phones (uses SBC on VM installed in Azure), Windows 3CX desktop apps, and 3CX mobile phone apps, all of these have the same symptom for external calls. It is not clear if only the IP phones use the SBC or desktop/mobile apps do as well (that seems unlikely), so it does not seem to be a problem with the SBC install while considering all of these work for extension-to-extension calls.

The system uses Flowroute which all seems to be set correctly. Most threads on this subject talk about checking firewalls, however, given this is hosted by 3CX, that does not seem to be the cause. Any thoughts on what else to check?

 

[MontEnt]

The same firewalls and settings are in place prior to the migration, so that does not seem to be the cause on the client side, the firewall checker on the 3CX instance passed all tests. There is not much to configure in terms of SIP settings, however, given external/internal phones ring when called indicates Flowroute is being contacted and authenticated.

3CX hosted seems to have removed some setting screens, including logging.

 

[MontEnt]

Apparently the trunk option for SIP/SDP IP was migrated with the old 3CX instance IP address in it, after updating this to the hosted 3CX instance public IP, inbound/outbound calls worked with 2-way sound: