In the past few months, we encountered audio problems using an IPSec vpn to connect to our phone system. As such, we decided to connect our phones directly. While this has improved the audio quality for trunk based calls, we are suddenly facing problems with making calls from one extension to another. Some connections don't ring when being called by another extension and others fail with "No Media". We also introduced secure SIP to improve security. So, we might also have a configuration problem caused by that. Furthermore, we have encountered problems with the 3CX client on Windows and Android. Any help is appreciated!