About ssl configuration issues

Hello, I am trying to create a writefreely instance, because of debugging the certificate I applied for let’s encrypt reached the limit this week, now I only have private.key and certificate.crt——wildcard certificate, verified by dns, but the standalone secure 443 (manual) mode does not seem to recognize them, I How should I configure to make my certificate apply to writefreely? My environment is debian11+nginx+sqlite3, I know nothing about code and linux, I hope you could understand my question, thank you!

I changed a domain and applied for a .pem certificate, but it is also not recognized in this mode. How should I set it?
By the way, if I use reverse proxy mode and use certbot to auto-configure the certificate it results in 502 error…The nginx conf file is configured according to the documentation provided by the official website.

I solved the problem of standalone mode, because I don’t need to reverse proxy, so I didn’t consider the reason of this problem.