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ChoiSapalo-2054 avatar image
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ChoiSapalo-2054 asked emilyhua-msft edited

535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit aka.ms/smtp_auth_disabled for more info.

Currently we have an application for sending out emails, in our previous setup we could use email facility for sending out with any problem . Right now we are encountering an error on sending emails using application

535 5.7.139 Authentication unsuccessful, SmtpClientAuthentication is disabled for the Mailbox. Visit aka.ms/smtp_auth_disabled for more info.

office-outlook-itprooffice-exchange-online-itpro
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KyleXu-MSFT answered KyleXu-MSFT commented

@ChoiSapalo-2054

From this article, we can know that we need to check settings below:

Connect to Exchange online with PowerShell.

Make sure the transport level is enabled

 Get-TransportConfig | Format-List SmtpClientAuthenticationDisabled

Then check the SMTP AUTH is enabled on the mailbox that you used to send emails:

 Get-CASMailbox YourMailbox | fl SmtpClientAuthenticationDisabled

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@ChoiSapalo-2054
I am writing here to confirm with you any update about this thread now?
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