Tunnel website hangs on load page

I use a tunnel like described here https://www.crosstalksolutions.com/cloudflare-tunnel-easy-setup/
But the website (thingsboard) keeps hanging at the load page (3 dots)

Any idea what is going on?

I use docker on ubuntu 20.04 for the connection (and thingsboard runs on http without docker)
This starts the tunnel connection
sudo docker run --add-host=host.docker.internal: Cloudflare/cloudflared:latest tunnel --no-autoupdate run --token …

Some update I got in chrome
Failed to load resource: the server responded with a status of 404 ()

In firefox I get a few of these
Loading failed for the with source “https://tb.*******/polyfills.e2023dc3442f7c8d.js”.

So for some reason it doesn’t get any of the resources.

Problem solved I wrongly added ‘/home’ to the tunnel path
hence the website could not change to ‘/login’