phpBB : Critical Error

Error doing DB query userdata row fetch

DEBUG MODE

SQL Error : 144 Table './schradthp/phpbb_sessions' is marked as crashed and last (automatic?) repair failed

SELECT u.*, s.* FROM phpbb_sessions s, phpbb_users u WHERE s.session_id = '15c2d8b5f5bc7a523a32ab4ce4e3ee72' AND u.user_id = s.session_user_id

Line : 325
File : sessions.php