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✉️ Email Delivery

Documentation, reference material and tutorials for CRM-NG SMTP Email: setup guides for every mail service, troubleshooting, and one article per error message.

Error: AADSTS50194: single-tenant application (Microsoft 365)

Updated

By Duane GarnerChief Executive Officer (CEO)
Summarize: Claude ChatGPT View Markdown
On this page

The Tenant ID field holds a shared value such as "common" instead of your own tenant. Enter your Directory (tenant) ID.

This article is for sites using the 365 / Outlook mailer where the token request to Microsoft fails with code AADSTS50194.

The error as you see it

Microsoft 365 token request failed: AADSTS50194: Application '…' is not configured as a multi-tenant application. Usage of the /common endpoint is not supported for such applications…

Shown by the 365 / Outlook mailer, in the failed-send banner, in Tools → Debug Events and in the Email Log.

What this error means

Before each batch of sending, the plugin asks Microsoft Entra ID for an access token at an address that includes the Tenant ID you saved. Microsoft also accepts a few shared values there, such as common and organizations, which mean "work out the tenant for me". That shortcut is only allowed for apps registered as multi-tenant. Your app registration is single-tenant (the normal and safer choice), so Microsoft wants your own tenant named explicitly.

Common causes

  • The Tenant ID field contains common, organizations or consumers, often copied from a generic example.
  • Settings imported from another plugin stored one of those shared values.
  • The field holds something other than the tenant, such as the Object ID of the app, and an older setting fell back to a shared value.

How to fix

  1. Open your app registration

    Go to https://entra.microsoft.com/, then Identity → Applications → App registrations, and open the app you created for this site.

  2. Copy the tenant ID

    On the app's Overview page, copy Directory (tenant) ID. It is a long ID in the form xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. While you are there, also note Application (client) ID.

  3. Leave the app single-tenant

    There is no need to change Supported account types. Making the app multi-tenant would also remove the error, but it opens the app to sign-ins from other organisations for no benefit.

  4. Update CRM-NG SMTP

    In CRM-NG SMTP → Settings → General, with 365 / Outlook selected, paste the value into Tenant ID. Your tenant's domain, such as yourcompany.onmicrosoft.com, also works. Check that Application (Client) ID matches the app. Press Save Settings.

  5. Send a test

    Go to CRM-NG SMTP → Tools → Email Test, fill in Send To and press Send Email.

Verify it worked

The test page shows "Test email sent successfully! Check your inbox to confirm delivery." The error no longer appears in Tools → Debug Events.

Notes

  • If you have constants in wp-config.php for this mailer (CRMNG_SMTP_*), the settings page cannot change them. Edit the constant for the tenant ID there instead.
  • A different code, AADSTS90002 or AADSTS900023, means the tenant ID was not found or is not well formed. See 400 invalid_request.
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