Samsung Knox sample app INSTALL_FAILED_DUPLICATE_PERMISSION and java.lang.SecurityException: Admin does not have android.permission.sec.MDM_APP_MGMT

Question

I downloaded the App Management Sample app from https://partner.samsungknox.com/dashboard/sample-apps

I added my License in Constants.java and I run it on my Samsung Galaxy Tab A (M.Y. 2016 with Android 6)

When it tries running I got:

Installation did not succeed. The application could not be installed: INSTALL_FAILED_DUPLICATE_PERMISSION

It turns out that the problem is related to:

<permission
     android:name="com.example.supportlibclient.SUPPORT_PERMISSION"
     android:label="Support permission"
     android:protectionLevel="signature" />

Any modification to this permission definition (removing it, changing the permission name, etc.) makes the app run, but it leads to a java.lang.SecurityException: Admin does not have android.permission.sec.MDM_APP_MGMT when I want to install, uninstall, disable enable an application.

For example, when setDisableApplication is called, a SecurityException is catched.

private void disablePackage(String packageName) {
    EnterpriseDeviceManager enterpriseDeviceManager =
                        EnterpriseDeviceManager.getInstance(this.getApplicationContext());
    ApplicationPolicy appPolicy = enterpriseDeviceManager.getApplicationPolicy();
    try {
        boolean appDisabled = appPolicy.setDisableApplication(packageName);
         mUtils.log(getResources().getString(R.string.disabled_app_result, appDisabled));
    } catch (SecurityException e) {
        mUtils.processException(e, TAG);
    }
}

Any idea about how to fix this? It seems a basic problem, and I cannot understand why the sample app is not working.

Thanks