No matching endpoint found

Yesterday all my communication systems switched off because of a power failure. After power was back, all systems are online but incomming calls do not arrive.
I have FreePBX The trunk to the provider is online and outgoing calls can be made.
The error message on incomming calls is:
[2017-07-30 11:35:14] NOTICE[1827]: res_pjsip/pjsip_distributor.c:526 log_failed_request: Request ‘INVITE’ from ‘sip:[email protected];user=phone’ failed for ‘’ (callid: p65547t1501407314m294556c26768174s2) - No matching endpoint found

This configuration worked for several months.
Has anybody a tip what could be the error?