I have a user that is getting Invalid INV when he picks up his handset to make a call. The user then has to unplug and plugin his ethernet cable to return to normal. I am also seeing the following in the asterisk error log:
[Nov 10 08:24:29] WARNING chan_sip.c: Maximum retries exceeded on transmission email@example.com for seqno 101 (Critical Response) – See doc/sip-retransmit.txt.
The phone becomes un responsive when this happens you can’t even telnet into the phone. Has anyone seen this before?