Why doesn't internal communication work during unsuccessful trunk registration in asterisk?

Question

Asterisk

Installed assembly FreePBX 14, there are 8 trunks. When the Internet is lost, the trunks try to re-register after a certain time. At the time of re-registration (approximately 3 seconds for each trunk, 25 seconds in total), the internal communication does not work (it seems that the SIP signaling does not work): it is not possible to make a call to the internal number, the softphone registration does not pass (there are no errors, it just hangs for a long time) . As soon as the attempts stop, or if you turn off all the trunks, then everything works as it should. Has anyone encountered such a problem? How can you decide?
upd:
Faced the same problem on another server. There was Internet there (dns worked correctly), but the provider was not paid, so the situation is the same: during trunk attempts to log in, internal communication and registration of new peers did not work

Answer 1

asterisk problems with dns
hangup solution chan_sip.so
Caching DNS paired with Asterisk

Answer 2

I agree with the previous commenter.
When it was necessary to restore functionality urgently, I made srvlookup=no on the server, and registered the necessary ip + domains in /etc/hosts.

Answer 3

I will also join, only a caching local DNS will save you.
By the way, not only Asterisk perceives the lack of a working DNS so painfully, some other services may also work inadequately.