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 ('338a2346a4bb3fcd7c3ac63a47db0325', -1, 1553343762, 1553343762, '365acce9', -4, 0, 0)

Line : 187
File : sessions.php