phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '6334f536b8cdc51fa9830d5ce560fd60' for key 'PRIMARY'

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('6334f536b8cdc51fa9830d5ce560fd60', -1, 1406645245, 1406645245, '3651d364', -9, 0, 0)

Line : 187
File : sessions.php