Need help on Webpacker issue with Rails 6

I am using Rails 6, Ruby 2.7, and Webpacker 4. X
I am getting below error
ActionView::Template::Error (Webpacker can't find application.js in /Users/developer/Documents/Projects/knowhub/public/packs/manifest.json. Possible causes:

1. You want to set webpacker.yml value of compile to true for your environment unless you are using the webpack -w or the webpack-dev-server.
2. webpack has not yet been re-run to reflect updates.
3. You have misconfigured Webpacker's config/webpacker.yml file.
4. Your webpack configuration is not creating a manifest.

Can anyone help me with this?