App Map is Blank Grey

This is probably because you are using a phone that doesn't run an official version of Google Android. Such as a Meizu phone, which runs FlymeOS.

In some cases simply installing Android System WebView will fix the problem.

Otherwise you may need to install Google Play Services
You can use an app like Play Services Info to verify Google Play Services is installed on your phone and the version it's running.

Some international Meizu phones might not even have the Google Play App Store installed, so you will have to first install "GMS Installer" from the FlymeOS App store, which will install the Play Store on your phone.