To connect google calendar you need to make the following action in Cog / Add-ons / Teamlead / Calendar:
Add Google app Api Key - AIzaSyAnFxttkLJra2KoTm8sVxTrdVKM4-n3M1E
Add Google app Client Id - 599718121269-buv3fccevr1bbttbtjngck58g19fnsip.apps.googleusercontent.com