With the retirement of Google sheets v3 api, replaced by v4, CHILI publish also implemented these changes.
The deprecation date for the v3 api is June 8, 2021.
CHILI publish has made changes in the setup to connect to this datasource, to allow you to keep using your datasource connection.
What to do?
On google cloud platform
https://console.cloud.google.com/apis/dashboard
Select your application that is used in CHILI publisher (on the top there is a dropdown) and hit ENABLE APIS AND SERVICES.
Select Google Sheets API and Drive API and enable both of them.
Google Drive API
Changes at the CHILI publisher side
In backoffice find your datasource and generate a new access code.
Push “Get new access” code, confirm your choice, copy the code into the datasource page and save the settings.
Use the right file type
On your Google Drive, make sure the source file type is Google Sheets, and not Excel.
If not open the file and select File - Save as Google Sheet.