Windows Active Directory connection unstable

Attempt to connect to netlogon share failed with error: [EFAULT] could not obtain winbind interface details: Winbind daemon is not available. could not obtain winbind domain name! failed to call wbcPingDc: Winbind daemon is not available..

2021-04-09 14:02:42 (Europe/Prague)

I can fix it manualy with these steps:

1. uncheck "Enable" on "Active Directory" page + "Save"

2. remove entries in "Kerberos realms" and "Kerberos Keytabs"

3. proceed with "domain join" on "Active Directory" page => AD healthy and everything is OK

after 3-4 hours again message about winbind and AD connection lost.

second truenas on same network no issues...

the same is happening with different customer on another network, one truenas still loses connection to AD because of winbind, second truenas deployment no issues...