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 ('851c0be6cc40ad0a4ff4d34ecc28f857', -1, 1513394860, 1513394860, 'ac444144', -1, 0, 0)

Line : 187
File : sessions.php