If you are upgrading to 3CX Version 16.X from a previous version. Please read this as you could be affected.
There is a bug in 3CX Upgrade Scrips which may cause you some issues. However, we have put together this guide to help resolve the issues that may occur.
Version 16 Introduces a new feature called “Auto-Discovery” This is ticked/enabled on new installs, however, due to the bug, on upgrades, it is disabled which would mean the SIP Trunk would show offline and not work for calls.
See the below screenshot. Simply ensure this box is ticked.
The second part is the upgrade loses some important settings under the Inbound Parameters Tab.
Please ensure the Call Source Identification is set up as the below screenshot. Otherwise, inbound calls will not work.