Asterisk Re-registering of the trunks

Hello! Please somebody give me an adviсe!

I register my provider’s trunks with this section in users.conf:

[TRUNK_NAME] host = provider's_host username = my_login secret = my_secret context = MY_CONTEXT type = friend group = null hasexten = no hasiax = no hassip = yes registeriax = no registersip = yes trunkstyle = voip outboundproxy = provider's_host fromuser = my_login authuser = my_login insecure = port,invite contact = my_login disallow = all allow = ulaw,alaw,gsm
But sometimes - without any regularity - the trunk (any of them) is disconnected for 1-3 minutes. It could be for example 3 times in a day, but also it could be 1 time in 3 days.

Maybe I could find the solution by trying to change the defaultexpiry, maxexpiry, minexpiry parameters?

I tryed to change the registertimeout, but it didn’t help me.