phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'phpbb_sessions.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 ('36cd4f34f5bc0a0a9a82b82aaab6b0a5', -1, 1768186852, 1768186852, 'd849d897', -9, 0, 0)

Line : 187
File : sessions.php