Ionic serve and build error

Hello I get this error when I serve the aplication.

but src\assets*** is there


the strange thing is that the aplication works fine, at least in the browser. But when i build the release apk it take ages to load the aplication in de device (all i can see is a blank page) and then this error pop out

this is how im building the release apk:

cordova build --release --prod android

i’ve also tried

cordova build --release android (this one is worst it take like 40 seconds to load the app, and then it shows the error)

i am using the latest version of ionic, if anyone can help thanks