업데이트/재구축 오류 코드 1 (3.1.0.beta4 -> 3.3.0.beta3) - Redis 포트 6379 관련?

It sounds like your setup was installed before Let’s Encrypt; there’s no need to manage certs by hand. I’d probably recommend moving to a new VM (I bet your OS it beyond end of life too?). See Move a Discourse site to another VPS with rsync.