Connecting Google Drive with the Coursepress Pro can be a bit tricky, you will need to add a Client ID also along with API key for Google Drive.
Follow this process to be able to embed files and documents from Google Drive in your courses.
Click this link
Click on 'Create Project' button
Give your project a name and click on 'Create'
Click on 'Credentials' link in the left sidebar
Click on 'OAuth consent' tab, enter a product name and click on 'Save'. You can leave the rest of the fields blank.
Now click on 'Create Credentials’ dropdown button and select OAuth Client ID
Now you have your Client ID created. You are almost there. Let's create your API key! Click on 'Create credentials'dropdown button again and click on 'API Key'
Choose 'Browser Key' from the popup
Enter the domain name int the format *.yourwebsite.com/* (without ‘http') and click on 'Create' button
Click on Library menu from the sidebar
Search for 'Google Drive API', click on it and enable it
Go back, search for 'Google Picker API' and enable it
Now copy Client ID and API Key from the 'Credentials' page and paste them in your website's 'Cloud Settings' page. You will find this page in the dashboard of your website. Go to settings --> EAD Coursepress --> Cloud Settings.