It is possible to use self-signed certificates. we use them in our development environments, they are generated when you make init.
We don’t recommend using such certificates for any other purpose than development, which is also why the Getting Started guide explicitly says that it won’t explain how to do that.
In case you’re using your own private CA, you’ll need to make sure it’s not only trusted on the host, but also in the containers.
What does the frontend of the Console show about the error? Can you check with the web developer tools of your browser what the value of window.PAGE_DATA is?