User removed from tmg group set

Hi All

we are using TMG 2010 to restrisct access to owa/activsync from the internet we are using TMG group set to add the allowed users who are required access to owa/activsync from the internet. But users automatically disappearing from the intermittently. we got to add them again to the groupset.

I have cheked the below article and we have not created restricted group.

http://social.technet.microsoft.com/Forums/en-US/33a65ba3-53b2-4af1-ba3a-dc0cd68a49cc/users-are-removed-from-group-set?forum=Forefrontedgegeneral