Symptoms
All websites on the server require user authorization.Cause
The server is infected by a virus. The virus has most likely used the MailEnable vulnerability. Virus infection causes a change of the Local Security Policy, all users, except for Administrators, are denied access to the computer from network. In Start, Administrative Tools, Local Security Policy, Local Policies, User Rights Assignment the field "Access this computer from network" is empty. Any new user added to the field gets removed when the MMC is opened again.Resolution
Depending on the Server type: Dedicated Server, or a Virtuozzo VE, there are different steps to resolve the problem.For a dedicated server
1. Download the hotfix http://download1.swsoft.com/Plesk/Autoupdate/Windows/ME-fix/me-fix.zip
2. Unzip into any folder, for example C:\tmp
3. Restart the server in Safe Mode.
4. Launch the command prompt: Start > Run > cmd
5. Change the current directory to C:\tmp\dedicated (cd c:\tmp\dedicated)
6. Start: cscript fix.vbs
7. Restart the server in Normal Mode.
For a VE with ID $veid
Solution in this part applies the fix for all VEs on Hardware Node.
1. Download the hotfix http://download1.swsoft.com/Plesk/Autoupdate/Windows/ME-fix/me-fix.zip directly to Virtuozzo Hardware Node.
2. Unzip into any folder, for example C:\tmp
3. Launch the command prompt: Start > Run > cmd
4. Change the current directory to C:\tmp\vz (cd c:\tmp\vz)
5. Start: fix.cmd