This is the standard advice we give on the Help Desk re this problem:
At the sign-in screen
http://www.able2know.com/forums/login.php , be sure to check Log me on automatically each visit.
Also, be sure that cookies are enabled. This will assure that your log-in will remain until you log out.
Otherwise, log-ins expire after a few minutes.
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But there is also a lot of glitching going on because of the work being done on the site.