phpBB : Critical Error

Error creating new session

DEBUG MODE

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

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, is_robot, session_admin) VALUES ('55c32337c4df8be96fe6ddbfb6100f0f', -1, 1469420110, 1469420110, '1714f7c5', 6, 0, '0', 0)

Line : 174
File : sessions.php