phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '55618cf3886c73fe28971e7e01eac6d4' for key 1

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('55618cf3886c73fe28971e7e01eac6d4', -1, 1485027012, 1485027012, '36d3d595', 0, 0, 0)

Line : 187
File : sessions.php