phpBB : Critical Error

Error doing DB query userdata row fetch

DEBUG MODE

SQL Error : 144 Table './tmbra_default/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 = '796fc8b7d272446fb51b4ca04cb487dd' AND u.user_id = s.session_user_id

Line : 315
File : sessions.php