I’ve just downloaded Gillion. I haven’t made any changes yet but I’ve noticed that my posts aren’t being found.
For example, I make a post “Example” with “abc” as its content. I get 404. Link below. The same is also true for the posts I downloaded from demo content.
Sorry to hear of the problem you are having.
To resolve the issue could you please go to your site permalink settings as shown in the attached screenshot and resave the settings?