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 ('3751f804124bc84719f8c884ae99c569', -1, 1542753526, 1542753526, '36a75f33', 4, 0, 0)

Line : 187
File : sessions.php