Having trouble setting up Nginx

I'm trying to set up a domain to more easily access my services on my home network, using a vanity URL instead of IP:port. With my current setup, my browser is not able to see the server ('we can't connect to the server' at e.g. plex.mydomain.xyz).

I registered the domain through Cloudflare. In Cloudflare, I set up my DNS records (A - mydomain.xyz - content = 192.168.x.x; A - www; CNAME - *), and got my API token. Nginx is running in Docker (as are the services I am trying to access), using the jc21 container and their docker compose template. I used the API token to generate an SSL certificate in NPM with *.mydomain.xyz as the domain, then added a proxy host using the URL mentioned above as the Domain Name, the IP of the server that's running all my containers for the forward hostname/IP, and the appropriate port for forward port. Then in the SSL tab told it to force SSL and HTTP/2.

I'm not sure what I'm doing incorrectly, the only thing I have running that might interfere with the network service is a PiHole, and it appears to be sending the request on. Also tried using localhost (127.0.0.1) to no avail. I've seen some others say they had to restart NPM a few times, so I've tried that as well. Thanks for any help!

*Edit: My router had DNS rebind protection enabled which was blocking the local address. I discovered this by using NSLOOKUP on my home network, where I got a 'No internal type for both IPv4...' error (in Windows command prompt) and outside my home network, where it resolved correctly. Thanks to those who commented, appreciate your time.