HA on centos 8

I followed https://nuxref.com/2020/11/25/perfect-home-assistant-centos-8-installation/ and installed the latest HA app. It was a straight forward installation. The steps are laid out clearly. The HA service started up but no web page. Instead, I’m getting 500 Internal Server Error. I have no idea how to even begin troubling the issue. Can someone help please?