Note that in every case I am accessing the site at http://asimplereader.com

Why do you need it to listen using the hostname? I’m not sure if thats correct syntax, if it is then maybe your droplet can’t resolve that or something?

I would change that block to this:

server { 
    listen 1.2.3.4:80; 
    server_name asimplereader.com;
    location ~ ^/ { 
        proxy_pass http://localhost:8081; 
        proxy_http_version 1.1; 
        proxy_set_header Upgrade $http_upgrade; 
        proxy_set_header Connection 'upgrade'; 
        proxy_set_header Host $host; 
        proxy_cache_bypass $http_upgrade; 
    } 
}

Does that do anything for you? Note - replace 1.2.3.4 with your IP..

MarkF, I’m listening by hostname so that I can host multiple sites (each with their own hostname) on the same virtual machine.

If you want to host multiple sites, just modify the the servername directive and making one of them a defaultserver.

Listen directive do nothing for virtual hosting but listen on a specific interface.

Since every droplet will only have 3 network interface max (ipv4, ipv6 & loopback interface), listen direct don’t have much use, unless you want to control which website to face ipv4 & ipv6.