I get this error on the secondary almost everyday.
Event Type: Error
Event Source: CiscoUnity_AuthenticationMgr
Event Category: Run
Event ID: 1000
Error from Win32 call to LookupAccountName: error 0x800706FC The trust relationship between the primary domain and the trusted domain failed.
We only have one domain and it looks like an NT4 error.
I have heard that removing the server from the domain and then readding it might fix this.
Can you even do that with a Unity server?