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 ('ce75e6a0358e21097e03eb7567c7c228', -1, 1728097922, 1728097922, '2cdcfbec', -2, 0, 0)

Line : 172
File : sessions.php