Related Content not showing on simple blog theme

Hi, I’m using the simple blog demo and when I publish a new blog, the related content doesn’t show even though it has been enabled in the theme options. When I check the other posts made by default, they all have the related content in the bottom and I can’t figure out why my posts don’t show it. I have already added categories and categorized the posts with the same one, but still. Can you please help? Thanks.