Google Calender setup not working

I would like to buy the pro version of emclient, but I can’t seem to be able to set up google calender (just the calender, no gmail). What does it mean, I have to connect through the web interface first - when I connect to Google through the browser I still can’t connect with eM Client.
Thanks for any hint.

Hi, if you’ve not checked your calendar yet on the google interface, please login to your calendar at and login using your credentials, this is a needed step for activating your calendar.

If the issue persists, please make a screenshot of the error you’re seeing and submit it here on the forum.

Thank you,