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 ('15a8e71f90dd8d8faae5481c34416db5', -1, 1558648901, 1558648901, '3417ea07', 2, 0, 0)

Line : 187
File : sessions.php