Calendar Integration using Azure AD Graph Explorer

Zoom Support has advised me to log a case we are experiencing with Zoom Integration to Microsoft 365 Room Calendars using Graph Explorer.

We currently have the Legacy Authentication based Calendar Integration working and trying to move away from it to the new Graph Authentication. We have it all up but when the Zoom Dedicated account tries to sign in, we see this error in Azure AD Sign-ins.

Status: Failure
Continuous access evaluation: No
error code: 70000
Failure reason: Provided grant is invalid or malformed.
Additional Details: Developer error - the app is attempting to sign in without the necessary or correct authentication parameters.

Can someone help please or guide me to the right place to get this resolved?