NGINX Proxy Manager not directing to specified port

I’m kind of new to this so apologies if I don’t know a lot.

I just signed up for the domain today, so I’m wondering if that has something to do with it.

But I have a local IP set with a domain I got from godaddy, and I have it set to access a certain port. So when I click on my.unique.domain, it should send me to 100.0.5.0:9999 (not it, just a placeholder). But instead it gives me a 403 error. But, if I type in my.unique.domain:9999 it goes to where I want it to.

And if I type https://my.unique.domain it no longer gives me the 403 error, but instead send me to the root 100.0.5.0 without the port i want.

So essentially all I’ve done is replace the local IP with a web address, but I still have to type it in in the same format as if I were straight typing the IP to get to where I need to go.

Is this just because the domain is new, and I need to wait? Or is this something else?

I also tried to use an API Key to get https but NGINX is giving me an error, and I’m guessing these issues are tied.

Thanks in advance for the help!