sip registration falls off on 1 number in Asteriske, everything is fine on the other numbers?

Question

Asterisk

sip registration falls off on 1 number, on the other numbers everything is fine, and at a specific place, the devices changed, the wire too. The IP address is received but not registered. And register for 30 minutes and then everything disappears

Answer 1

What registration expire value is configured on the devices?
Are the devices on NAT with respect to Asterisk?

Answer 2

Use the program to dump SIP traffic. Analyze what's going on.
1. Install on the server with SNGREP asterisk ( https://github.com/irontec/sngrep#installing). It can always come in handy for you in the future, it's a "must-have" for sip telephony.
2. Run - "sngrep number_that_falls off" (for example, "sngrep 101").
3. Leave to work for 1-2 hours, wait for it to fall off.
4. As a result, how it fell off - open one of the last dumps with REGISTER messages, and watch the phone's communication with the PBX.
If it's difficult, we can help if you save the dump and show it to us. There you can save dialogs in the program.