Built panel plugin doesn't load

I have created a new plugin via npx @grafana/toolkit plugin:create . I added the visualisation to a dashboard but I get an error alert “Error loading: my plugin name”.

In the dev tools console there is the error:

GET http://localhost:3000/public/tslib?_cache=1640355273357 404 (Not Found)

I haven’t changed any of the code in the generated plugin, just built it. All I have done is install the latest version of postcss due to an error encountered when building.

All seems to be ok now - I was using NPM, but switched to Yarn as per the tutorial.