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 ('9356dcb904bc1e0eaa33c555e243dfcb', -1, 1566593963, 1566593963, '22ecbed8', 2, 0, 0)

Line : 187
File : sessions.php