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 ('4c7f8c0e5b88efb51c10cd0ee0e1979c', -1, 1571222571, 1571222571, '22ccbf1f', 31, 0, 0)

Line : 191
File : sessions.php