Terminal service stopped working and the started working automatically

[tek1ket]

In Our company all users have to mak a VPN Connection to ISA Server (windows server 2003) to work with internet.but today something happened ,non of them could make a VPN Connectionn , and also i could not make a terminal connection to the server. i Get this message when i wanted to make terminal connection

The client could not connect to the remote computer.
Remote connections might not be enabled or the computer might be too busy to accept new connections.
It is also possible that network problems are preventing your connection.
Please try connecting again later. If the problem continues to occur, contact your administrator.
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OK Help
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and also i found this error in event viewer

Event Type: Error
Event Source: TermService
Event ID: 1036
Description:
Terminal Server session creation failed. The relevant status code was 0x2740.

after a few restart the windows or Terminal service and Remote Access Connection manager , it worked and every thing went ok.

i searched the internet and found this article

http://support.microsoft.com/kb/555382

i cann't edit the registry because everything was ok for years and the services also get worked after a few restart, so i want to know what cause this problem

any idear is appreciated

Thank you