Samsung Galaxy App Not Installed Exception

Question

I am trying to deploy an update of an existing Mobile application & keep getting the following exception:

"App Not Installed"

Q: What am I doing wrong?
Q: Is there a way to see or activate ERROR messages?

I have the following:

• Samsung Galaxy S9+
• 42 GB free disk space
• 3 GB memory available
• No SD Card

I am using the following APK file:

• com.[companyname].pulse.apk
• ...in my Phone\Download directory
• ...and it shows up in the "Installation Files" listing
• ...this is NOT the signed file (is that right?)

I have done the following:

• Gone to "Install Unknown Apps" and verified "Allowed" is checked for "My Files"
• The 1st time I accessed it...I was forced to choose "Allowed"...as well
• Enabled "Developer Options" through the "About Device" menu's

I developed using:

• Xamarin.Forms (2.5.0.280555))

Answer 1

This is my FIRST attempt at any mobile application...so...as it turns out:

• Drop the SIGNED APK file onto your phone
• Install using the SIGNED APK file
• When installing, a PLAY STORE prompt will appear...choose "Install Anyway"

You're done.

To be fair, someone in the office told me to use the UNSIGNED APK file...which turned out to be bogus.