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 ('3bff8dc84398eaa41f86ab76abaecce7', -1, 1571111295, 1571111295, '03e3026d', 1, 0, 0)

Line : 191
File : sessions.php