At first I saw some errors:
pjsip: tsx0xa908f11c .Failed to send Request msg OPTIONS/cseq=47035 (tdta0xa3dbedb0)! err=320046 (No working DNS nameserver (PJLIB_UTIL_EDNSNOWORKINGNS))
pjsip: tsx0xb3fd360c Failed to send Request msg OPTIONS/cseq=37043 (tdta0xa6dd23d0)! err=70009 (Operation timed out (PJ_ETIMEDOUT))
I have experienced problems with chan_sip if dns service was unresponsive.
after sometime phones started to unregister:
res_pjsip/pjsip_configuration.c: Contact 101/sip:[email protected]:5060 has been deleted
res_pjsip/pjsip_configuration.c: Endpoint 101is now Unreachable
And they did not reregister after that.
I have restarted asterisk - now everything works fine.
What is it? How did it happen? How to prevent it?