Theme Customizer Won't Load

I am just getting started with WordPress for the first time for my first attempt at a blog and I have created my profile. Anyways I select a theme and then go to customize it and the side bar on the left shows up but the preview page won’t load. It just continues to load for hours. I’ve tried different themes. I’ve tried different computers. I’ve tried using chrome and safari. I’ve tried to uninstall and reinstall wordpress. Anyways everything I’ve tried doesn’t work. I’m not sure what to do…anyone have any ideas what I should do? I’m debating if I should just go to Blogger or something else for this if I can’t figure it out. It’s so frustrating 🙁