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 ('cd0e78235e9075e2cc4e7d7074db17ac', -1, 1464358084, 1464358084, '36c62a5d', 4, 0, '0', 0)

Line : 174
File : sessions.php