phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '7471f8f0b59f6400577786dafeb8dcbb' 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 ('7471f8f0b59f6400577786dafeb8dcbb', -1, 1770500672, 1770500672, 'd849d8d9', -10, 0, 0)

Line : 187
File : sessions.php