APK fails when created for production

When I generate the APK with…
ionic cordova build android --prod --release
this fails to install in Hardware device

ionic cordova build android
the apk install OK.

What is the technical difs between debug and production version, a part of console outputs?

“fails to install” is very vague and doesn’t give anybody much to go on. Error messages would be helpful, as would a publicly-accessible MCVE.

Thanks for your answer. No more to add. When I try to install the APK created with -prod -release parameters, this says: “The APK Failed to install”. Word more, word less. Some related to unsigned app? Any ideas?