Terminal Server Refuses New Connection.

Problem: Terminal Server Refuses New Connections

Error: Event Log Shows 'The terminal server received a large number of incomplete connections. The system may be under attack.'

Problem is caused by too many logon /logoff actions at the same time.

Obviously this could be caused by an attack but if you're like me, it was caused by too much activity at once.

Resolution:

In HKLM\System\CurrentControlSet\Control\TerminalServer , add the following DWORD value: MaxOutstandingConnect

You will need to add the value in hexadecimal format.

For Example:
50 is entered as 32 hex
75 is entered as 4b hex

Then reboot the server and your issue is resolved.

This has been tested and validated on the following OS's:

Windows Server 2008
Windows Server 2008 x64
Windows Server 2008 R2