Starting HTML server on Lightsail Windows instance

I created a new Windows Server 2019 instance on Lightsail. I'd like to use it to serve web pages from a small application I'm making using Panel (a Python library based on Bokeh and Tornado). So far I've been unable to connect to the HTML server -- I get a timeout from my browser, and the log messages from the server don't show any attempt to connect.

What I've done so far:

• created a static IP address for my machine
• installed Python and all the libraries I need for my application
• launched the server using the default settings, which allow connections from the local machine on port 5006
• verified the application was running by using Edge to connect to http://localhost:5006/app (replacing "app" with the name of my application)
• restart the server, this time using --allow-websocket-origin='*' (a Bokeh option needed when connections are coming from the outside; I've tested this option on my local network)
• configure the firewall on the Windows OS to allow connections on port 5006
• tried connecting to my server from an outside system, with the URL http://nnn.nnn.nnn.nnn:5006/app (using the static IP address of my Windows instance)

When that didn't work (no connection made), I tried restarting the server with another option that told it to use port 80, and tried the same URL but without the port number, but that didn't work either.

Any help would be appreciated...