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 ('954071ef1eccae5d1ff8da10e2697379', -1, 1566115574, 1566115574, '12e835e7', -9, 0, 0)

Line : 187
File : sessions.php