phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 144 Table './unitedheroes/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, session_admin) VALUES ('d3b6b0321c48d063b721bbb92854f871', -1, 1513038244, 1513038244, 'ac453e2a', 4, 0, 0)

Line : 187
File : sessions.php