In a basic sense, ERR_CONNECTION_REFUSED means that the domain that you are trying to connect to isn’t accepting your request. From the screenshot it looks like localhost is refusing that connection, which might be due to a number of reasons, including antivirus software, security settings, or even a different piece of software listening on the default port.
When I look at the Local log, I do see a few messages that look like this:
{"thread":"main","class":"Process","process":"nginx","level":"warn","message":"nginx: [emerg] bind() to 0.0.0.0:80 failed (48: Address already in use)","timestamp":"2021-09-01T10:21:16.103Z"}
This part:
[emerg] bind() to 0.0.0.0:80 failed
basically means that Local couldn’t use the default port for HTTP. You’ll likely need to enable localhost Router Mode from “Preferences > Advanced.”