phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 145 Table './phpBB/phpbb_sessions' is marked as crashed and should be repaired

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('ac7b4b8f4e61c3b0a44bdaa5ec47c2c6', -1, 1438749354, 1438749354, '369f340a', 15, 0, 0)

Line : 187
File : sessions.php