This could be a file corruption issue due to low available disk space in ofcserver.ini and/or TrendClnPermisionDef.payload.

To resolve the issue:

1. On the OfficeScan server, search for C:\program files (x86)\Trend Micro\Officescan\PCCSRV\Private\ofcserver.ini and check its size. If the file size is 1 KB, it might indicate an issue of low or out of disk space.
2. Once the disk space is released, find a backup copy from ...\Trend Micro\Officescan\PCCSRV\Backup.
3. Stop the OfficeScan Master Service.
4. Replace the 1 KB file using the backup file.
5. Log in to the OfficeScan console as a root account.
6. Verify the agents in the Agent Management Page. If the agents failed to show up, stop OfficeScan Master Service and replace PCCSRV\Private\AuthorStore\TrendClnPermisionDef.payload from the previous backup file.
    

   If there is no backup file, copy the TrendClnPermisionDef.payload file from another OfficeScan server.
7. Restart the OfficeScan Master Service.
8. Log in again to the OfficeScan web console as a root account.
9. Remove and re-add the AD accounts under Administration > Account Management > User Accounts.
10. Log in using an AD account and verify its permission.