You tried to link your Google Calendar to the Event Feature but you got a "This app is blocked" warning. The warning does not provide any means for you to proceed further and you cannot link your Google Calendar.
When linking your Google account to sync a Google Calendar to the Event feature, you received the following warning:
This app is blocked
This app tried to access sensitive info in your Google Account. To keep your account safe, Google blocked this access.
This warning is recently changed from 'This app isn't verified' and offered an 'Advanced' link that would allow you to bypass the warning to 'This app is blocked' with no 'Advanced' link or link of any kind. Currently, there is no way to bypass this message. Our Development Team is aware of the issue and is working to resolve it. Watch our Release Notes for the announcement that this is resolved.