Appwrite Function's URL cannot be reached

Hello, guys.

I am running Appwrite on my domain appwrite.example.com. It is listening to 2780 and 27443 for HTTP & HTTPS respectively. On the same server, I have Nginx Proxy Manager running on 80/443, forwarding every request to appwrite.example.com and *.appwrite.example.com to the Appwrite instance on port 2780 (e.g. http://ip:2780). SSL certificates are valid from NPM.

Below are the configs in the .env:

_APP_DOMAIN=appwrite.byh.uy
_APP_DOMAIN_FUNCTIONS=appwrite.example.com
_APP_DOMAIN_TARGET=appwrite.example.com

I then publish a Function from local via appwrite publish. It was assigned the URL 67665f63720fb17ef7f9.appwrite.example.com. However, the URL doesn't work. I tried all sorts of HTTP methods, such as GET, POST, PUT, etc., but it always timed out. The code was very simple too:

export default async ({ res }) => {
    return res.json({
        motto: "Build like a team of hundreds_",
    });
};

So now I'm stuck. Any advice is highly appreciated!