Dynamics Community Forum Thread Details

How to use OAuth 2.0 to send email via SMTP in Microsoft BC On Premise Version (W1 26.2)?

Due to the Microsoft is retiring Basic Auth for SMTP AUTH (Client Submission) on Exchange Online
Disabled by default in late December 2026 for existing tenants, with a final removal date to be announced in second half of 2027.
(Source: https://techcommunity.microsoft.com/blog/exchange/updated-exchange-online-smtp-auth-basic-authentication-deprecation-timeline/4489835)

We are trying to use the suggested OAuth 2.0 for SMTP Authentication. In BC, we have found this as below,

During verify the authenticate,

BC will generate an incorrect internal redirect URI which is using 'http'. I have asked our technical support vendor and seems this redirect URI cannot be edited.

Therefore, i have never can verify the authentication and cannot use this OAuth 2.0 to send email.

Same as my subject of this post, how to use OAuth 2.0 to send email via SMTP in Microsoft Business Central On Premise Version (W1 26.2)? Thank you!

Categories:

Dynamics 365 Business Central

Hello,
for Business Central on-premise, OAuth 2.0 for SMTP will not work with a random/generated redirect URL if Microsoft Entra does not have the exact same Redirect URI registered; the fix is to configure BC to use your real HTTPS Web Client URL, then register that same URL in Entra as a Web redirect URI, normally like https://YourBCServer/BC260/OAuthLanding.htm (must match the browser URL, including instance/path, but usually not :443 if the browser hides it). If BC is generating http://..., then your on-prem Web Client/BC configuration is still exposing itself as HTTP, so fix SSL/public web client URL first, then create/use a custom Entra app registration, add the required SMTP/Exchange permission/consent, run Set up Microsoft Entra ID / Email Microsoft Entra application registration in BC, and then configure the SMTP account with smtp.office365.com, port 587, OAuth 2.0, Client ID, Tenant ID, Client Secret, and the same Redirect URI; also confirm SMTP AUTH is enabled in Exchange Online, otherwise the OAuth login can succeed but sending still fails.

Regards,
Oussama Sabbouh

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