Connecting Teams calendars with external services like Outlook for unified scheduling
Hi, I'm Diane and I'm happy to help you today.
Are you using the same Microsoft 365 account for both Teams and Outlook calendar?
If the account is the same, the calendar will show up in Teams automatically. If they are not in the same Microsoft 365 account, such as if the mailbox is on another email host, the calendar won't be available in Teams.
Let me know how it goes, I'm here to help you further if needed.
-- Diane