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 ('cb7fd4c8fbe60035d6145744ce15cfc0', -1, 1548024699, 1548024699, '64182e0a', 19, 0)

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