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 ('8f62c77f5af06607eb28ea7d806f54e9', -1, 1558450716, 1558450716, '6b17814d', 16, 0, 0)

Line : 187
File : sessions.php