Hi,
You’ll probably have more useful help very soon by others, but I ran into similar issues lately after clean install, where I couldn’t have the message with my attributed IP.
What do you have if you run the following?
systemctl status -l rockstor
Mine was reporting the rockstor service as inactive, so I simply run systemctl restart rockstor and after a few seconds, I could access the web-UI and complete the setup process (with my hardware, it takes a minute or two before the web-UI actually works).
Hope this helps!