phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '-1' for key 'session_user_id'

INSERT INTO oka_phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in) VALUES ('2760b9aa81ebbc1ad8c7afe2b81173e2', -1, 1550515772, 1550515772, '36d23d29', 26, 0)

Line : 184
File : /home/c128/public_html/talk/includes/sessions.php