I’d reckon your Settings > Asterisk SIP Settings are wrong, probably with pjsip on the wrong port - it’s confusing and IIRC there are several settings that need to be “in agreement”.
Settings > Advanced Settings > (Dialplan and Operational) SIP Channel Drive = "both"
Settings > Asterisk SIP Settings > Chan SIP Settings > (Advanced General Settings) Bind Port = "5060"
Settings > Asterisk SIP Settings > Chan PJSIP Settings > (Transports / udp) Port to Listen On = “5061”
I didn’t make any notes at the time, but I remember getting in a muddle when I tried changing the first one to “pjsip”, thinking I only wanted to use that driver. Everything went wobbly until I reverted to the above settings (which I believe are the default). In any case I’ve since realised that using pjsip is probably not a good idea unless you specifically want its capability for multiple devices for one user.
If this doesn’t fix your problem then we’d probably need more info about your setup.
EDIT: confirm also please what your endpoint hardware is and that you’ve configured it to talk to port 5061 on the server.