phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'ef74407e1e8a8b41a0a2a9da17daef40' for key 1

INSERT INTO phpbb2_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('ef74407e1e8a8b41a0a2a9da17daef40', -1, 1498156334, 1498156334, '36c6cda1', 11, 0, 0)

Line : 187
File : sessions.php