@rcpinheiro Thanks I tried this and it works.
My mistake is that I copied the whole project to www, I should have copied only the files under the dist folder (after running ‘npm run build’ in onsen)

I followed this instruction from OnsenUI’s website regarding how to deploy the app to android. https://onsen.io/v2/guide/hybrid/cordova.html#adding-onsen-ui

“Now that you have a basic Cordova app set up, getting Onsen UI working is simple. Remove all of the files inside Cordova’s www folder to get rid of all the sample code. If you have an existing Onsen UI website, all you need to do is put all the code inside www, and re-run the app as before.”

I literally deleted the contents of my www folder in my cordova project, then copy-pasted all of the contents of my OnsenUI project inside that www folder as is, but I encountered this error.

I already set these two permissions on android too: INTERNET & ACCESS_NETWORK_STATE

What should I do?