All calls, in and out, terminate upon connection while WiFi calling is enabled. When I disable WiFi calling, calls do not terminate but there’s no audio in or out. What could be causing this?

Hi,

Hm. Try to isolate the issue.

See if you can address these two issues separately :

WiFi calling disconnects;

Cellular : no audio.

Start with updating your device, if possible.

Turn off WiFi calling to troubleshoot the sound issue:

https://support.apple.com/en-us/HT203800

Also, don't forget, sometimes a simple restart will resolve the issue.

Extra information:

https://support.apple.com/guide/iphone/make-and-receive-wi-fi-calls-iphf90f372f0/ios

Please clarify. Are you stating that you do not have any cellular service?

Axel F.