Mail could not be sent to the recipients because of the mail server failure. SQL Server smtp relay O365 Exchange Online

Lucas Igbins 0 Reputation points
2024-02-04T13:11:55.1266667+00:00

Please can you help with the configuration you used that resolved your the issue. Error is he mail could not be sent to the recipients because of the mail server failure. (Sending Mail using Account 1 (2024-01-12T22:30:04). Exception Message: Cannot send mails to mail server. (Error in processing. The server response was: 5.7.3 STARTTLS is required to send mail [HBNBB2PR11CA0024.namprd46.prod.outlook.com 2024-01-12T22:30:04.588Z 08DC1349D89C1DDD]).
) TLS 1.2 is enabled on the server. Office 365 mailbox has smtp auth enabled My application owner is using similar setup on the SQL server. I am using this setup User's image

SQL Server
SQL Server
A family of Microsoft relational database management and analysis systems for e-commerce, line-of-business, and data warehousing solutions.
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Microsoft Exchange Online Management
Microsoft Exchange Online Management
Microsoft Exchange Online: A Microsoft email and calendaring hosted service.Management: The act or process of organizing, handling, directing or controlling something.
4,036 questions
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  1. Andy David - MVP 137.9K Reputation points MVP
    2024-02-04T13:51:52.3633333+00:00

    Ensure:

    1. Security Defaults aren't enabled ( You really shouldnt disable the security defaults if you arent enforcing MFA with a CA policy) https://learn.microsoft.com/en-us/entra/fundamentals/security-defaults
    2. Exclude the user from any Conditional Access policy that blocks Legacy Authentication
    3. Disable any per users MFA on the account.
    1 person found this answer helpful.