phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 144 Table './phpbb_1/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) VALUES ('ab9706f8e3aa32c17908f9cb870f5b32', -1, 1425556294, 1425556294, '3211a792', -1, 0)

Line : 158
File : /forum/includes/sessions.php