phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '99cfe8ae09d68e442619cc02b78fd689' 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 ('99cfe8ae09d68e442619cc02b78fd689', -1, 1466871815, 1466871815, '36c43427', -4, 0, 0)

Line : 187
File : sessions.php