nginx static files served on server using curl, but not to browser on remote machine

I'm working my way through my first nginx / gunicorn / flask deployment using a stock Amazon Lightsail Ubuntu server. At this point, I'm ignoring gunicorn and flask, and just trying to get nginx to serve my static files.

I am able to get a static file while ssh-ed into the server using:

curl -k https://localhost/static/test.txt

However, when I attempt to access the url https://my.ip.add.here/static/test.txt the request times out.

I'm running ufw with 80 and 443 (and 22) open, but even disabling it does not solve the problem.

I do not see any errors in /var/log/nginx/error.log or /var/log/nginx/access.log. (Although it appears that the logs don't contain my most recent successful curl attempts, do they need to get flushed in any way?)

Can anyone suggest what the problem might be, or where I should look for additional errors?

[UPDATE] Here are the results from ss-ntlpe:

State      Recv-Q Send-Q Local Address:Port               Peer Address:Port              
LISTEN     0      128               *:80                            *:*                   
users:(("nginx",pid=17623,fd=6),("nginx",pid=6845,fd=6)) ino:26170 sk:1 <->
LISTEN     0      128               *:22                            *:*                   
users:(("sshd",pid=1371,fd=3)) ino:16267 sk:2 <->
LISTEN     0      128               *:443                           *:*                   
users:(("nginx",pid=17623,fd=13),("nginx",pid=6845,fd=13)) ino:28373 sk:3 <->
LISTEN     0      128       127.0.0.1:8000                          *:*                   
users:(("gunicorn",pid=17582,fd=5),("gunicorn",pid=17580,fd=5),("gunicorn",pid=17578,fd=5)
,("gunicorn",pid=17577,fd=5),("gunicorn",pid=17574,fd=5)) uid:1000 ino:45243 sk:4 <->
LISTEN     0      128              :::22                           :::*                   
users:(("sshd",pid=1371,fd=4)) ino:16269 sk:5 v6only:1 <->