I have seen this answer: How to configure heroku application DNS to Godaddy Domain?. I am using 1and1, not GoDaddy. The docs https://devcenter.heroku.com/articles/custom-domains do not specifically mention the need for an add on. My custom domain does point to my home page on Heroku, but the links from the home page to other content get a 500 error, and only the mydomain.herokuapp.com shows up in the url, not the domain I paid for.
What is the CURRENT way this is supposed to work, why/how, and how do I get it so ALL pages on my site ONLY show my domain, not ...herokuappp.com? Thanks.