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Office 365: No incoming emails (451 4.4.4 Temporary server error. Please try again later ATTR5) RRS feed

  • Question

  • Hello,

    we have a problem for some hours now and no incoming emails.

    Setup: Our MX records points to our own pre-mailserver, which delivers all accepted mails directly to the xxxxx.mail.protection.outlook.com server. xxxxx.mail.protection.outlook.com is the address which, according to office365 advice, should be the MX record target. (xxxxx is just anonymized).

    Until tonight, it all worked great, but now for several hours, xxxxx.mail.protection.outlook.com rejects all the emails from our incoming email relay.

    Example of the mail queue log:

    3C18E303DF    26149 Tue Nov 22 08:48:16  sender@example.org
    (host xxxxx.mail.protection.outlook.com[xxx.xxx.xxx.xxx] said: 451 4.4.4 Temporary server error. Please try again later ATTR5 (in reply to MAIL FROM command))
                                             recipient@example.org

    Any ideas what we could do?

    Tuesday, November 22, 2016 11:53 AM

All replies

  • Hello,

    we have a problem for some hours now and no incoming emails.

    Setup: Our MX records points to our own pre-mailserver, which delivers all accepted mails directly to the xxxxx.mail.protection.outlook.com server. xxxxx.mail.protection.outlook.com is the address which, according to office365 advice, should be the MX record target. (xxxxx is just anonymized).

    Until tonight, it all worked great, but now for several hours, xxxxx.mail.protection.outlook.com rejects all the emails from our incoming email relay.

    Example of the mail queue log:

    3C18E303DF    26149 Tue Nov 22 08:48:16  sender@example.org
    (host xxxxx.mail.protection.outlook.com[xxx.xxx.xxx.xxx] said: 451 4.4.4 Temporary server error. Please try again later ATTR5 (in reply to MAIL FROM command))
                                             recipient@example.org

    Any ideas what we could do?


    Assuming you the Office 356 connector correctly setup, then you should open a case with Office 365 support.

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    Tuesday, November 22, 2016 1:10 PM
  • Dear Andy, thank you for your answer.

    I have opened a case within Office 365. They called me back and said, multiple customers had reported similar issues.

    While the problem was not solved, I tried out some more things:

    • Mails sent from Gmail are being received, if I ensure that gmail sends emails via the direct route to the office365 mx server (I did that via a conditional DNS server change).
    • At the same time, emails from our mail relay were rejected (same error message as above). This indicated that the problem was specific to our servers, most presumably the ip addresses.
    • I searched for my relay settings. We had a very similar problem some months ago. As a result, I had to add the IP address of our relay mailserver into a whiteliste in office 365. Unfortunately, I cannot find that whitelist setting in office365 at all - either the functionality to whitelist external smtp servers has been taken out of Office 365, or I am too stupid to re-find it.
    • I remember that the advice of the "do I need a connector" assistant was no a year ago. I would classify our setup as "partner organisation" setup - and the connector advisor today still said, it is optional to create one.

    However, I added the connector, as an internal one, configuring the subnet of our relay servers as "the organisation's email server".

    4 minutes later, the problem was solved.

    From my perspective as an IT professional, I am not satisfied with the Microsoft style of handling things. I would expect:

    • SMTP error messages which help finding a problem. Obviously, our IP address had been blocked, but the error message sent by the microsoft server indicated an internal problem at the Microsoft server.
    • A possibility to find out if and why our mailserver has been blocked by MS systems. Just for the record: we do not send any spam, and especially this relay server only relays mail from the internet to the customer - so no reason to block it (we are talking about peanuts: an average of 500 mails per day).
    • a support which is able to handle this kind of absolutely basic IT stuff. SMTP exists for 30 years now, the problem is clearly tracked down to "mail is rejected by receiving smtp server" within 30 seconds, but there seems to be no way to report it. I have to take all the way from Level 1 support (select "my email does not arrive"), and the support guys never heard of SMTP at all. Hard to explain the problem, in this case.
    • Information to the admins, before global mail filters are changed. As everything worked well for a year or so, and as we did not logon to Office365 nor changed our mail configuration, and as the problem occured to multiple customers independent from ours, it seems to me that something significant changed on the MS side. Without notice.

    The worst thing is, I do not know when the next change will make my connector configuration disappear and block the emails again. How can I prevent this from happening?

    Tuesday, November 22, 2016 5:46 PM
  • Dear Andy, thank you for your answer.

    I have opened a case within Office 365. They called me back and said, multiple customers had reported similar issues.

    While the problem was not solved, I tried out some more things:

    • Mails sent from Gmail are being received, if I ensure that gmail sends emails via the direct route to the office365 mx server (I did that via a conditional DNS server change).
    • At the same time, emails from our mail relay were rejected (same error message as above). This indicated that the problem was specific to our servers, most presumably the ip addresses.
    • I searched for my relay settings. We had a very similar problem some months ago. As a result, I had to add the IP address of our relay mailserver into a whiteliste in office 365. Unfortunately, I cannot find that whitelist setting in office365 at all - either the functionality to whitelist external smtp servers has been taken out of Office 365, or I am too stupid to re-find it.
    • I remember that the advice of the "do I need a connector" assistant was no a year ago. I would classify our setup as "partner organisation" setup - and the connector advisor today still said, it is optional to create one.

    However, I added the connector, as an internal one, configuring the subnet of our relay servers as "the organisation's email server".

    4 minutes later, the problem was solved.

    From my perspective as an IT professional, I am not satisfied with the Microsoft style of handling things. I would expect:

    • SMTP error messages which help finding a problem. Obviously, our IP address had been blocked, but the error message sent by the microsoft server indicated an internal problem at the Microsoft server.
    • A possibility to find out if and why our mailserver has been blocked by MS systems. Just for the record: we do not send any spam, and especially this relay server only relays mail from the internet to the customer - so no reason to block it (we are talking about peanuts: an average of 500 mails per day).
    • a support which is able to handle this kind of absolutely basic IT stuff. SMTP exists for 30 years now, the problem is clearly tracked down to "mail is rejected by receiving smtp server" within 30 seconds, but there seems to be no way to report it. I have to take all the way from Level 1 support (select "my email does not arrive"), and the support guys never heard of SMTP at all. Hard to explain the problem, in this case.
    • Information to the admins, before global mail filters are changed. As everything worked well for a year or so, and as we did not logon to Office365 nor changed our mail configuration, and as the problem occured to multiple customers independent from ours, it seems to me that something significant changed on the MS side. Without notice.

    The worst thing is, I do not know when the next change will make my connector configuration disappear and block the emails again. How can I prevent this from happening?

    Well, you can never absolutely keep it from happening if its a 365 issue.

    But at a minimum, you could restrict your admins in 365 and enable 365 auditing to determine who if anyone made a change.


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    • Proposed as answer by Jason.Chao Wednesday, November 23, 2016 8:43 AM
    Tuesday, November 22, 2016 8:08 PM