Actually I had the same problem as well.
my application runs and the map is blank!
First of all check whether you have installed Google Play in you android mobile.
actually I had the problem in API Key restrictions
Google Developer Console
- Login to Developer Console.
- In your Dashboard Navigation Menu.(left side)
- Select API & Services > Credentials.
- So you will be redirected to Credentials page were you can view all the API keys that you created (https://console.cloud.google.com/apis/credentials)
- Identify your Project API key and click on Edit Api Key.
- Under that you can see the Key restrictions
- From there remove all Application restrictions and Api restriction.
On your Android Mobile
- Uninstall the App.
Android Studio
- Build > Clean Project.
- Build > Rebuild Project.
- Run IT
This steps worked for me perfectly.
- Reference
GitHUb ,
Google Issue Tracker