Zoom Scheduler - can't reauthorize - find calendar

Hello,

I have a problem with the office 360 calendar. My user cannot reauthorize it or set it as the primary calendar. The options are grayed out. Every time they try to reauthorize, they get the same error message. I checked the permission settings for the 365 calendar and enabled read, write and shared access. But when I go back to the permissions page, shared is disabled. How can I fix this? I appreciate any advice. Thanks!