Cannot initiate calls using mobile data

[c-Viorel]

Version

3.4.1

File / Feature

Something strange starts happening a few weeks ago. Some users are not able to initiate a call using cellular data. Using wifi everything works perfectly fine. I couldn't find any relationship between ios version and current problem. (it may be an ios 13 issue? )

Expected behaviour

To be able to initiate calls using cellular data.

Actual behaviour

Randomly users are not able to initiate calls using their mobile data..

Stacktrace / Error message

none

Other info

none

[ShlomieRottenberg]

Are you using IPv4? Some carriers have started blocking VoIP calls over IPv4. One way around this issue is to use TLS. Or you can upgrade to IPv6.