Authentication domains need not to be resolvable.
It sounds from the logs as if your Kamailio is trying to forward the
REGISTER to the remote domain (i.e. calling t_relay()), and is unable to
do that because it won't resolve.
--
Alex Balashov - Principal
Evariste Systems LLC
235 E Ponce de Leon Ave
Suite 106
Decatur, GA 30030
United States
Tel: +1-678-954-0670
Web:
http://www.evaristesys.com/,
http://www.alexbalashov.com/