Symptoms
The error might be reported when attempting to create an Exchange backup set, after adding the Exchange connector, as a result, when trying to pick up a certain mailbox to be added to the backup items list, the operation will fail.Cause
The API permissions configured in Azure portal need to be approved by a Global Admin account (the App registration and API permissions were added and configured by a non-Global Admin account).
Workaround
To resolve the issue, you must log into Azure portal with a GA account, navigate to the app permissions page, and click on ‘Grant Admin Consent for company_name’.
The permissions page location: Azure Portal > Microsoft Entra ID > App Registrations, click on your newly added app, then click on ‘API Permissions’ button from the left side menu.