Hi Fabian!
It seems that the example config from that blog posts redirects 503 errors to that /deploy.html page. Please try following our own docu to configure Apache and use one of our own web-server recipes.
If it still doesn’t after applying that docu, please check the logs for more details of the 503 error.
Some context about that “deploy page” can be found here, but I’m guessing our down command will not work in your case.
Just for completeness & posterity’s sake: our official installation guide is here.