Fresh install so am I getting "Firefox can’t establish a connection to the server at localhost:3000"?

[ugreg]

Ran the following and choose all the default options, but unable to visit the app in browser.

react-static create

? What should we name this project? my-first-site
? Select a template below... typescript
Creating new react-static project...

Then I cd to the newly generated project directory and get ready to deploy.

yarn start

I get some good output

yarn run v1.22.10
$ react-static start
Starting Development Server...
Fetching Site Data...
[✓] Site Data Downloaded
Building Routes...
Importing routes from directory...
{ has404: true }
[✓] Routes Built (0.1s)
Building Templates...
[✓] Templates Built
Bundling Application...
Fetching Site Data...
[✓] Site Data Downloaded (0.1s)
Running plugins...
[✓] Application Bundled (15.9s)
[✓] App serving at http://localhost:3000

Then failure:

Doing a build a serve using npm instead of yarn bring up the site on my network, but on local host host it still does not run.

npm run build
npm run serve