Error with public device URL

I decided to try out Balena on my Raspberry Pi 3B+. I installed the image, and created my cloud account. After it booted, the device connected to Balena cloud, and I can see status, logs, console, etc. Then I turned on the “Public Device URL” slider. When I click the URL link, I get an error page that says “Tunneling socket could not be established: 500”. It looks like this:

What am I missing? Is there a server problem, or am I doing something wrong?

Hi Dennis

The public URL function works hand in hand with a container that you need to push on the device. Have you pushed any such container to your application?

The said application needs to expose a server - could be something as simple as python -m http.server 80 - on the said port, and then the contents of the folder, or whatever you are serving will be visible on the Public URL. The balenaOS or the supervisor don’t serve anything on the said port, so you won’t see anything by default there.

We have some good getting started guides, that you can download and deploy to your app -

If you see the server.js file in the source, you will see that it is serving some files on port 80. This will be available on your local network without doing anything, and will be available globally after you enable the Public URL flag in the dashboard