If you font list is empty, most probably the API key provided has done the maximum requests allowed by the Google API.
In our themes there is a field for the Google fonts API key. Many decide to change it to their own key, which is recommended, but not many succeed.
Here’s the process of getting an API key for Google fonts:
1. Go to https://console.developers.google.com/projectselector/apis/credentials
2. Select a project or start a new project
3. On the left side of the screen go to ‘Credentials’ tab and choose ‘API key’, then choose ‘Browser key’, give it a name and press ‘Create’.
4. Copy the given API key
5. From the left side of the screen go to ‘Overview’, in the ‘Other popular APIs’ section choose the ‘Web Fonts Developer API’.
6. Press ‘Enable API’.
Now you’ve got the key and activated it. You have to go to your theme options, typography and insert your key in the theme options panel!