Icon labels in buttons in Google Mail (Gmail) are missing / not showing / not displaying.
You have probably blocked the following URL address in the HOSTS file:
Sometimes forum users give you a list of addresses to block in the Hosts file, for various reasons. Make sure you understand where those URLs point to, if possible.
1. Open the file C:\Windows\System32\Drivers\etc\Hosts in Notepad or Notepad++ (make sure the file is not READ ONLY). Note: This file has no extension.
2. Remove the line from your Hosts file (or put a # at the beginning)
The line most likely looks like this:
3. Save the HOSTS file (set to READ ONLY, if desired).
4. Refresh the tab in your browser and Gmail should be back to normal. Problem solved.