Asterisk periodically throws "returned -1: Host is down" errors, what does this mean?

Question

Asterisk

Sometimes asterisk gets the following error for several hours
[Apr 7 16:59:21] WARNING[33904]: chan_sip.c:3705 __sip_xmit: sip_xmit of 0x2948e500 (len 544) to 192.168.0.106:5060 returned -1: Host is down
Out of 30 users, only one or two have this at the same time.
Even restarting the asterisk does not help.
As I understand it, this happens when the device is incorrectly turned off.
Google and Yandex are silent about this.

Answer 1

This also happens if the device's IP has changed without re-registering it on the asterisk.