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 ('c4cc2a014e9851005b2e3fd69d9db8e7', -1, 1571148937, 1571148937, '03e3f9ea', 4, 0, 0)

Line : 187
File : sessions.php