How To Prevent Random Google+ Users From Sending You Gmail

  1. Login to Gmail and click the gear icon at the top right corner of your screen.
  2. Select “Settings.”
  3. Under “General,” look for the setting “Email via Google+.” 
  4. Click the drop down menu and select the audience you want to have the ability to send you Gmail. I opted for “Circles.” 
  5. Scroll to the bottom and click “Save Changes.”