Ionic build vs ionic release (Parsing error)

Hi have a question. There are 2 commands.

$ ionic build android
$ cordova build --release android

For putting it on the google playstore, I should use --release.
But when I do that, and put the unsigned apk on my phone.
I get an parsing error.

But the debug apk works just fine.
Why is that? Or am I doing something wrong?
However google playstore accepts the APK file after signing & zipalign.

But I just don’t know if it works. I mean, even after signing… I still get a parsing error.

The release APK is meant to be used for Google Play submission or production level usage. So when you try to install the unsigned copy your phone will get rejected since it’s not signed.

There is a guide on signing the APK here, takes a minute or two