“You cannot install this app because another user has already installed an incompatible version on this device”

Refer this ,
Actually your debug version of the app didnt get uninstalled properly

1. Go to settings > apps > downloaded app list
2. You can see the installed applications in the list
   (the application may not be in order. or may be towards the very end)
3. Click on the application,go to the overflow menu option
4. Click on uninstall for all users options