I've been a Linphone user for several years. Since some time it
doesn't receive calls (although I can make calls). The problem
probably started when I upgraded Debian, which upgraded Linphone
to 3.12.0 from 3.6.1.
I'm using a commercial SIP provider. I can receive calls on my
Android on CSipSimple (on the same network). I briefly tried
Zoiper on my Debian system and it works too. I tried removing all
Linphone configuration and restarting from scratch, but I wasn't
able to improve anything. I attach the debug log (whose last few
entries repeat every 5 seconds for ever).