NLTest failure

I am not sure if this is a problem or not but it needs to be asked.  On my Exch box I am getting "The trust relationship between this workstation and the primary domain failed" with the MSExchangeFrontEndTransport as the source. Users are also getting prompted for passwords in Outlook. My network guy says FW\Routers\vlans are all good. DCDiag is good.  Running NLtest cmds are all ok except one NLTest /whowill:domain username. For some devices I get  

[10:33:44] Mail message 0 sent successfully (\MAILSLOT\NET\GETDC419B291A)
[10:33:49] Mail message 0 sent successfully (\MAILSLOT\NET\GETDC419B291A)
[10:33:54] Mail message 0 sent successfully (\MAILSLOT\NET\GETDC419B291A)
Didn't receive a response for mail message 0 (\MAILSLOT\NET\GETDC419B291A)
The command completed successfully

and other devices I get 

Cannot write netlogon mailslot: 53
Didn't receive a response for mail message 0 (\MAILSLOT\NET\GETDC1F93E9A3)
Can't stop response thread (TIMEOUT)
The command completed successfully