You are unable to log in to the user account “user_name” at this time I have a Mountain Lion server and two Mountain Lion clients. I have two network users. From one of the clients I can log on using either of these two accounts, from the other I cannot log using neither of these two accounts. So it is not a user account problem. The authentication seems to go through correct, judging from logs, but then it fails with the message from the subject of this post, with further remark that the login failed because an error has occurred no details on error. Both client Macs are bound to open directory in the same way. DNS works fine on both clients. Where should I go on server searching for error?

Update: after checking the client logs I found the problem (but not the solution)

22/4/13 9:13:01.556 PM NetAuthSysAgent[20445]: CFPreferences: user home directory for user kCFPreferencesCurrentUser at /Network/Servers/sandramini.private/Volumes/DataBackedUp/NetUserFolder/macme is unavailable. User domains will be volatile.


However, the folder is there, I can access it over AFP using the same credentials as when logging in with that user.
Also if I try to ssh with the same user, then I end up in the proper folder

togo:02-04 zmagyar$ ssh -l macme sandramini.private
Password:
Last login: Mon Apr 22 21:54:23 2013 from 192.168.3.10
sandramini:~ macme$ pwd
/Network/Servers/sandramini.private/Volumes/DataBackedUp/NetUserFolder/macme


So why does it not find it when trying to log as network user?
It was Little Snitch :-(
I found the solution here https://discussions.apple.com/thread/4676595?start=0&amp;tstart=0
First I put LS into silent mode, allowing all connections, but did not help. Then I disabled it completely and login worked.
Then at the new user login it reported that there were connections attempts during logon, I examined these, set them to permanent enabled LS and it works fine.
Here are the rules appearing on the net logon account:
NethAuthSysAgent allow outgoing connection to domain domainname (where the domain name is the domain you are logging into)
NethAuthSysAgent allow outgoing connection to ipaddress (where the ipaddress is the address of your OS X server, hosting the OD I guess)
opendirectoryd allow outgoing connection to ipaddress (where the ipaddress is the address of your OS X server, hosting the OD I guess)
I hope this helps some one out there