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 ('733dff7fb5928de39ee12d0f2a7020c5', -1, 1728524036, 1728524036, '2cc05fa1', -2, 0, 0)

Line : 172
File : sessions.php