One of my client is using Exchange SMTP Basic Authentication. It begin retiring SMTP Basic Authentication on March 1, 2026.
I have followed the steps to migrate to OAuth 2.0 in sandbox. It works for the internal member to send email in Business Central. However, there are some users who are guests in the tenant. They are assigned Business Central licenses, but don't have Microsoft 365 licenses. They are required to send emails in the tenant.
The error message is "The SMTP server rejected the authentication request, as the authentication data is incorrect. Verify that your Username and Password are correct and that the SMTP server supports the specified authentication type (OAuth 2.0). SMTP error code: 535.".
Apart from converting these users into internal users within the tenant and assigning them Microsoft 365 licenses, are there any other possible ways to resolve this issue?
Thank you for your reply! To ensure a great experience for everyone, your content is awaiting approval by our Community Managers. Please check back later.
2
Share
Report
All responses (
Answers (
