File Mover Blog

March 14, 2026

Office 365 SMTP OAuth2 Client Credentials Authentication with Certificate

Office 365 SMTP OAuth2 Client Credentials Authentication with Certificate Authentication

For use with Limagito File Mover requiring app-only SMTP access

We recently added SMTP authentication using a private key file to our ‘SMTP as destination’ option. We did this already with Azure and Sharepoint.

  • Destination Setup > Add <SMTP>

limagito file mover smtp as destination

  • Be sure to use Vendor 2 – CK

limagito filemover smtp as destination setup

  • Email setup:

limagito filemover smtp email setup

  • OAuth2 Setup:
    • If you prefer to use a Client Secret instead of a Certificate then you need to add it here
    • We left the Client Secret blanc because we are going to use a Certificate

limagito file mover smtp oauth2 setup

limagito file mover smtp authentication options

– Some Azure Screenshots used in the previous document:

limagito filemover azure setup

 

  • Azure App registrations:
    • Add a new registration here

limagito filemover azure app registrations

  • Application (client) ID and Directory (tenant) ID will be needed in the SMTP OAuth2 setup.

limagito filemover app registrations

  • Azure App registrations > Certificates & secrets
    • We used a Certificate but also a Client secret is possible, this is up to you.

limagito filemover azure certificates and secrets

  • Azure App registrations > API permissions

limagito filemover azure API permissions

  • Enterprise applications
    • Your App registration will be available under ‘Enterprise applications’
    • Application ID and Object ID will be used in the PowerShell commands of the Setup Guide.

limagito filemover azure enterprise applications

  • Exchange admin center > Recipients > Mailboxes
    • After using the PowerShell commands you should see
      • Send as (1)
      • Read and manage (Full Access) (1)
    • They both should contain a reference to the App registration used

limagito filemover azure exchange admin center

limagito filemover exchange admin center

limagito filemover exchange admin center

  • RunTime Log Result:

limagito filemover smtp runtime log result

 

If you need any help with this ‘SMTP OAuth2 Client Credentials Authentication’ setup, please let us know.

Best Regards,

Limagito Team

#smtp #filemover #managedfiletransfer #filetransfer #filemanagement

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