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SMTP Email Setup

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Posted on by CU04021004-0

Hello Everyone,
I have done SMTP email setup with OAuth 2.0 , but when i send test email , then i got this error,
Anyone have any idea why this is happing ?

Could not authenticate on the SMTP server.

451: 4.7.0 Unrecognized authentication type

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Dynamics 365 Business Central

Microsoft Dynamics NAV

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Jun Wang 8,200 Super User 2025 Season 2 on at

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Are you setting up smtp for a customer as a partner or set it up for your own company? It would help to share a screenshot of the smtp setup page to add clarity.

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Suresh Kulla 50,243 Super User 2025 Season 2 on at

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Please review this

https://yzhums.com/54545/

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Ramesh Kumar 7,527 Super User 2025 Season 2 on at

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Yes, please remember that the MFA feature needs to be turned off, and the distribution list won't work. It should be an individual or shared mailbox

https://learn.microsoft.com/en-us/dynamics365/business-central/admin-how-setup-email

Thanks

Ramesh

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Jainam M. Kothari 15,631 Super User 2025 Season 2 on at

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Hello,

The error message "451: 4.7.0 Unrecognized authentication type" typically indicates that the SMTP server does not recognize or support the authentication method being used.
Please find the below mentioned steps to resolve the issue:

Verify OAuth 2.0 Configuration: Ensure that your OAuth 2.0 setup is correctly configured. This includes checking the client ID, client secret, and token endpoint URL in your Business Central settings.

SMTP Server Settings: Double-check the SMTP server settings. Make sure that the server supports OAuth 2.0 authentication. Some servers might require specific settings or additional configurations to enable OAuth 2.0.

Update Business Central: Ensure that you are using the latest version of Business Central. Microsoft frequently updates the platform to support new authentication methods and protocols.

May this can help : https://learn.microsoft.com/en-us/dynamics365/business-central/admin-how-setup-email

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Ashwin Nimbulkar 164 on at

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try this:

https://yzhums.com/54545/

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Khushbu Rajvi. 20,275 Super User 2025 Season 2 on at

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Hope this helps: https://learn.microsoft.com/en-us/dynamics365/business-central/admin-how-setup-email

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