Error when building my first app!

Music: Teacher faces porn charges.

Error message:

Error while executing: am start -n "com.actualcopy.fortune/com.actualcopy.fortune.MainActivity" -a

android.intent.action.MAIN -c #
android.intent.category.LAUNCHER
Starting: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] cmp=com.actualcopy.fortune/.MainActivity }
Error type 3
Error: Activity class {com.actualcopy.fortune/com.actualcopy.fortune.MainActivity} does not exist.

Error while Launching activity!

Background:

I had created a rendition to the "Hello world!" app on android studio 4.0 working with Java. The build was successful and I have the .apk file available with me. However, I am unable to get it to work on the emulated device.

Running device: Pixel 2, API 27

Inspection:

1. Uploaded the .apk on the emulated device and installed it.
2. Wrote an ASO for the App, just saying!
3. Tried to upload the .apk on an older device, device faulty!

Note: The .apk is a debug APK file and I haven't the difference between that and the standard.