mail遭退信

Question

我們使用公司本身建立的mail server 透過 outlook寄送信件給gmail常常遇到退信 退信內容如下

FYI

-----Original Message-----

From: Mail Delivery System <******@......com.tw>

Sent: Monday, January 29, 2024 3:30 PM

To: ******@......com.tw

Subject: Undelivered Mail Returned to Sender

This is the mail system at host mail.epmed.com.tw.

I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can delete your own text from the attached returned message.

                   The mail system

<******@gmail.com>: host gmail-smtp-in.l.google.com[173.194.174.26] said:

    550-5.7.26 This mail has been blocked because the sender is

    unauthenticated. 550-5.7.26 Gmail requires all senders to authenticate with

    either SPF or DKIM. 550-5.7.26  550-5.7.26  Authentication results:

    550-5.7.26  DKIM = did not pass 550-5.7.26  SPF [epmed.com.tw] with ip:

    [61.216.119.158] = did not pass 550-5.7.26  550-5.7.26  For instructions on

    setting up authentication, go to 550 5.7.26

    https://support.google.com/mail/answer/81126#authentication

    f16-20020a635550000000b005cfbdff9195si5247321pgm.783 - gsmtp (in reply to

    end of DATA command)

Answer 1

Hello A- HAO,

Thank you for posting in the Microsoft Community! We are happy to assist.

Based on your description, Your emails to Gmail keep bouncing/rejected with the error message " 550-5.7.26 This mail has been blocked because the sender is unauthenticated. ". Feel free to correct me if I misunderstood.

Upon checking your email server address mail.ep***.com.tw in SPF checking tools, it shows that the domain and the email server do not have any SPF records published.

From NDR seems you are using own mail service, so it is suggested to contact your email service provider to check this query and update your records.

If you are Microsoft365 business user and haven't update records yet, please check :

the method to create and publish an SPF record for your domain, alongside DKIM and DMARK, depends on your DNS provider.

Here are more details about TheService Provider Foundation (SPF). | Microsoft Learn,Set up SPF to help prevent spoofing On Office 365 | Microsoft Learn

and Use DMARC to validate email | Microsoft Learn

I hope the above information will be helpful. Please feel free to let me know if you have any other concerns or if I get you wrong. Glad to assist you. We sincerely appreciate your patience and cooperation. Thanks for your precious time!

Please understand that our initial reply may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution.

Best regards,

Microsoft Community Moderator