Grandstream (UCM61xx aka Asterisk) SIP (TLS) works weird why?

Question

Asterisk

I noticed a very strange thing,
the trunk was raised to the TLS + SRTP sipnet for some time, then it stops.
I do Wireshark, I don’t see packets at all towards the sipnet, I reboot it works for a while and then stops again (I don’t know the exact time).
I switch the whole thing to UDP + SRTP / RTP = it works stably.
PS
It seems to me that I saw something similar on Asterisk 1.8.7 (but I'm not sure) the same problem.
Has anyone encountered something similar?

Answer 1

There is no registration (incoming calls are not needed), only outgoing calls, and how does registration affect the fact that the asterisk stops making requests?