phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '87f25101510f697e3546641c85517399' 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 ('87f25101510f697e3546641c85517399', -1, 1498522580, 1498522580, '36c6c89d', 15, 0, 0)

Line : 187
File : sessions.php