Install shows error in console: INSTALL FAILED CONFLICTING PROVIDER
The authority, as listed in android:authorities must be unique. Quoting the documentation for this attribute:
To avoid conflicts, authority names should use a Java-style naming convention (such as com.example.provider.cartoonprovider). Typically, it's the name of the ContentProvider subclass that implements the provider
If you have different flavors and you want to avoid collisions in the authority name you can add an applicationIdSuffix to build types and use the resulting applicationId in your manifest, like this:
<... android:authorities="${applicationId}.contentprovider"/>
This can also happen when you have an older version of your app installed and made changes to the (support) library or the manifest file. Deleting the old applications from your device (Settings --> Application --> <your application> --> Uninstall) will solve the issue then.