Service Principal (Client Secret)

Follow these steps to enable the Microsoft Exchange Organization agent to access Exchange Online using a service principal with client secret.

For more information see

Logon to the Azure Portal as a user account with sufficient permissions.
Go to Microsoft Entra ID > App Registrations > New Registration.
Enter an appropriate name for the application - for example "XIA Configuration Exchange".
For supported account types select
Accounts in this organizational directory only
Do not specify a Redirect URI.
Click Register.
Go to API Permissions
Click Add a permission > APIs my organization uses > Office 365 Exchange Online
Select Application Permissions when prompted
Select Exchange.ManageAsApp

Click the Add permissions button
Click the Grant admin consent link
Go to Certificates & secrets > Client secrets.
Click the New Client Secret button.
Enter a description and the expiry for the client secret.
Click the copy button next to the value for the client secret and make a note of this value. This value is only available at this point.
Click Overview > Application Name under the "Managed application in local directory" header.
Make a note of the Application ID and Object ID.
Goto Microsoft Entra ID > Roles and administrators > Global Reader
Select Add assignments and search for the service principal that was created - for example "XIA Configuration Exchange" and click Add.
On a machine with the Exchange Online PowerShell cmdlets installed open PowerShell and connect to Exchange Online interactively using appropriate credentials.

Connect-ExchangeOnline
Execute the following command to create a corresponding Service Principal in Exchange Online using the AppIication ID and Object ID noted above.

New-ServicePrincipal -AppId "00000000-0000-0000-0000-000000000000" -ObjectId "00000000-0000-0000-0000-000000000000" -DisplayName "XIA Configuration Exchange"