Trying to use SSL on NAS hosted site

I have a site that I am hosting on my own NAS… and I don’t think that is really the issue, but I have a website that I have made local on my network that I am able to view here:

https://192.168.50.100/wordpress

I know you cannot see that – however… if you goto my site at the public address:

https://4andahalf.farm/

I have my hosting company perform a stealth redirect to:

https://4andahalf.ddns.net/wordpress

Which is my no-ip.com domain that updated my WAN IP because I do not have a static address.

So my scan of my site states:

Detected status of your setup.
You have the required PHP version to continue.
SSL certificate should be generated and installed.
The PHP function CURL has successfully been detected.
<strong>The Hosting Panel software was not recognized. Depending on your hosting provider, the generated certificate may need to be installed manually.</strong>
Alias domain check is not relevant for a subdomain
<strong>It is not possible to install Let's Encrypt on a subfolder configuration. For more information, please read this article

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The last bold item I am not sure what that means. Whats steps do I need to take to secure the site?

The page I need help with: [log in to see the link]