Organizing, editing, and coordinating meetings and events within Microsoft Teams calendars
Hi Michael,
The error message "Access denied for the resource" together with tag [4k709] may indicate an account permission or tenant configuration issue. This can occur if the required Microsoft 365 permissions are not assigned, access to Microsoft Teams is restricted by organizational policies, or the account is attempting to sign in to the wrong organization.
Since the Teams Meeting add-in depends on a successful sign-in to the Teams desktop application and a Teams-enabled Microsoft 365 account, the sign-in issue would need to be resolved first before the add-in can appear and function correctly in Outlook.
As these settings are typically managed by your organization's IT administrator, I recommend contacting them and providing them with the Correlation ID and Timestamp from the error message so they can review the sign-in failure and account configuration.
In case you do not know who your IT admin is, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support.
You may also share the following Microsoft resource with the IT admin. It explains how to use the Teams sign-in diagnostic in the Microsoft 365 admin center to check your account and identify the root cause: Self-help diagnostics for Teams administrators - Microsoft Teams | Microsoft Learn.
I hope this response reaches you in time and helps bring some clarity. If you have any question, feel free to reply.