Hi Sushant,
I too had similar issues but in GP10. I run the following script on DYNAMICS and kill the user session. I hope it may help you....
SELECT USERID, LOGINDAT, LOGINTIM
FROM ACTIVITY
GROUP BY USERID, LOGINDAT, LOGINTIM
HAVING (USERID NOT IN
(SELECT TOP (100) PERCENT loginame AS LoginName
FROM sys.sysprocesses
WHERE (dbid > 0)
GROUP BY dbid, loginame
HAVING (DB_NAME(dbid) = 'dbname')
ORDER BY LoginName, DB_NAME(dbid)))
ORDER BY LOGINDAT
--DELETE FROM DYNAMICS..ACTIVITY WHERE USERID = 'userid'