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 ('af3a1833014c3f6e1a3682dc935d4a88', -1, 1553544328, 1553544328, '22e42a19', 36, 0, 0)

Line : 187
File : sessions.php