Question
Calendar and Contacts integration being blocked by Google
Recently I found that new users in my organization were no longer able to set up calendar and contacts integration with our Google Workspace account. Each time they clicked past the Google account selection screen, they got an alarming "This app is blocked" message.
I solved it by going to Admin > Account Management > Account Settings, scrolling to Calendar and Contacts, and deselecting the "Read" permission for Mail.
I hope this helps someone.