Before, I had coded an android app on my laptop, and when I built the APK file for the app, there were no issues with installing it on my phone. However, after resetting my laptop and reinstalling Android Studio, I have been facing a problem. Every time I build the APK file and try to install it on my phone, Google Play Protect doesn't recognize the app error is displayed. Any Solution?

not kotlin but kotlin colored But maybe it has to do with the signing of the APK. When building an APK, it will be signed; With a release APK, this will be obvious, because you need to supply a signing key. But the APK will also be signed, even when it’s a debug-version. This will be done with the debug.keystore file, in your home folder. This debug.keystore file is generated automatically when first needed. When you re-install your PC, this debug.keystore file is lost, and re-generated. Trying to update (re-install) an app on your phone that was signed with a different key, will result in an error. Uninstalling the app from your phone, and doing a fresh install, should fix the issue.