Yes this is a strange one and we have seen it before. It is likely that your issues with:
are related to this ‘re-generate’. It may be that you are missing something the Rockstor depends upon.
Take a look at the following issue where there are instructions on re-generating our specific nginx configuration using the template included within the /opt/rockstor directory:
The second comment there has a one line command string that, assuming you have an empty nginx, will re-create it from the template.
@petermc@kysdaddy and @Zonk in the following forum thread has confirmed this to work (repeated in forum thread):
Hope that helps. You didn’t mention re-generating your nginx via this route so I though it best to start with that as a possible cause.