Hmmm - usually RADIUS should be sending a session timeout with the number of seconds until the account expires.
Make sure the system clock is correct on the UserMan and on the Mikrotik.
When we used FreeRADIUS, if we specified an expiration time on an account, and a max session time, then the server would send a session-limit of X seconds, where X was the lesser of those two values. (so if the account expires at midnight, and the current time is 23:57, then the session-limit would be 180sec)
Look in the Hotspot Active tab, and lok for the "Session Time Left" column. There should be a value there counting down to zero. If not, then UserMan isn't sending the value. Perhaps the local user profile's values are overriding the RADIUS value...
Thank you for replying .. it turned out to be a very simple problem ,am sorry i made you write all these lines .
I misunderstood "validity" in the user manager, i thought it is the one who should kick the user out,after more digging i discovered the limitations.
Thanks again,my problem was solved