Can't connect to local sites?

I haven’t used Local in a while, but have tried unsuccessfully a lot this week. Up to this morning, Local wouldn’t even start for me – so I went back and made sure everything was updated, reinstalled, and… it’s running!

But now I can’t view any of my local sites. It always says that my browser can’t connect, no matter what site I run.

I’m working on mac OS high sierra. What am I doing wrong?