Has anyone ever put a VoIP trunk with Swisscom SIP credentials into operation on this PBX? In the dashboard, "Available" appears for this trunk if I enter everything correctly. However, I am then prompted on the extension with "The call was rejected. Please try again later." when I want to make a call to an external number. The Swisscom data must be correct, everything works with the Android app "ZoiPer". It also works from the Grandstream PBX when I enter a second trunk with data from another SIP provider and switch the "Outbound Rule". Something special obviously has to be set on this Swisscom trunk, but Swisscom doesn't offer support with SIP because there are too many manufacturers. Does anyone have experience and know what has to be set additionally/differently (I have already been able to find the "Outbound Proxy" myself)?