Hugo can't see theme

I’m trying to create a blog with hugo using a theme called Sustain. When I run hugo server, the blog looks fine, just the way I wanted. But when I run hugo only, the html page I get its not configured accordingly with the theme. It has no configuration. Anyone knows what might be happening?

Here’s the netlify page: (i put it there before knowing it wasnt working)

Looks like baseurl in your config.toml is still set to Try changing to the netlify address or a simple “/” and you should be okay. When you run server on your machine, it assumes localhost - that’s why it worked there.