phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('f78f2b5fe7324f0d3ff4fbdc40a616d9', -1, 1728481957, 1728481957, '03ee524d', 0, 0, 0)

Line : 172
File : sessions.php