I have been having quite a bit of trouble wrapping my head around this issue.
I register to ITSP and that is fine. Outgoing works ok. Incoming does not seem to work:
SIP/2.0 403 Incorrect Authentication
SIP/2.0 403 Forbidden
Reason: Q.850;cause=57
sip-ua authentication is configured to match and passwords double checked
problem is resolved by adding the ITSP username to the ephone-dn
I don't really understand why this makes a difference authentication-wise
ephone-dn 100
number 100 secondary 1777MYCCID no-reg primary
