The situation is as follows:

1. We have all the server OES2SP3 + postfix
2. We have configured CIFS server
3. We have a server in AD W2K8R2.

Cifs authentication is configured through the domain.

Between eDirectory and AD synchronization is set up mirror (IDM), including passwords and users.

Volume on the CIFS server by default. Customers who logs in only to get access to the AD volumes natively without entering a password and get on Maps of the network drives.

This scheme works like day or less days, after which access to network drives for users disappears.
Pops up a window to enter a network password on the network to the ball.

After restarting CIFS on the server without reloading the client AD and without re-registering, users gain access to network drives.
Sometimes you have to overload the CIFS daemon twice a day.
There are ideas that are at the stage of authorization?

Code:
Jun 22 12:03:34 fs2 CIFS[2543]: CRITICAL: AUTH:   select error !!                                                                                            
Jun 22 12:03:34 fs2 CIFS[2543]: WARNING: AUTH:   PDC readSocket returned: -1 bytes, reset PDC connection, socket error : Bad file descriptor                 
Jun 22 12:03:34 fs2 CIFS[2543]: WARNING: AUTH: DcncShutDown: Closing PDC session                                                                             
Jun 22 12:03:34 fs2 CIFS[2543]: WARNING: CODIR: SESNotLoggedIn: Failed to authenticate user: SPlotnikov from 192.168.16.30, nwErr: 222, cifsErr: 0           
Jun 22 12:03:34 fs2 CIFS[2543]: CRITICAL: AUTH: Bad password. tempSES->nwLoginError is 222                                                                   
Jun 22 12:03:34 fs2 CIFS[2543]: ERROR: DCNC: Failed to send sessionsetup req to PDC, Connection reset by peer                                                
Jun 22 12:03:34 fs2 CIFS[2543]: WARNING: AUTH:   PDC readSocket returned: 0 bytes, reset PDC connection, socket error : Connection reset by peer             
Jun 22 12:03:34 fs2 CIFS[2543]: WARNING: AUTH: DcncShutDown: Closing PDC session                                                                             
Jun 22 12:03:34 fs2 CIFS[2543]: WARNING: CODIR: SESNotLoggedIn: Failed to authenticate user: SPlotnikov from 192.168.16.30, nwErr: 222, cifsErr: 0           
Jun 22 12:03:34 fs2 CIFS[2543]: CRITICAL: AUTH: Bad password. tempSES->nwLoginError is 222                                                                   
Jun 22 12:03:34 fs2 CIFS[2543]: WARNING: AUTH: Signing enabled : reset connection with PDC                                                                   
Jun 22 12:03:37 fs2 CIFS[2543]: WARNING: AUTH: Signing enabled : reset connection with PDC