Application not installed on android devices - Ionic4

I have developed an android application using Ionic4. I am facing an issue when installing the apk in to android devices. I have seen similar questions but didnt get and proper solution . I have used the command

ionic cordova build android --prod --release

This will generate un-signed-release.apk but when I try to install it shows application is not installed . If I run the command Ionic cordova build android --prod will generate debug apk and can install on devices.

I dont want to sign the apk as I am not uploading to stores. I just want to run it on the devices. Any help?

Ionic Info


   ionic (Ionic CLI) : 4.12.0


   NodeJS : v10.15.3
   npm    : 6.4.1
   OS     : Windows 10