Join Log in
Score:0
avatar Server

Outlook / MS Exchange from Office 365 returns 550 header syntax

us flag
DonCziken

A client of mine has a case that a partner company is not able to deliver e-mails to them. The case is that they receives following information returned by Mailer-Daemon:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

recipient@office365-based-email.com
host 192.168.101.200 [192.168.101.200]
SMTP error from remote mail server after end of data:
550 header syntax

However exactly same message send to recipient@gmail.com or literally any other mail system works perfectly fine and reaches its destination.

What I have tried so far:

  1. Adding mail flow, which would bypass spam filter
  2. Sending test e-mail through various e-mail clients
  3. Checked mail flow reports for failures
  4. Checked message trace

but either no traces of those messages.

So:

  • does anyone have a clue what might be the reason?
  • have an idea where to search?

Following is example message source (hidden actual e-mail addresses and content):

From: sender@other-3rd-party-mail-service-provider.com
To: recipient@office365-based-email.com
Subject: ABC
Thread-Topic: ABC
Thread-Index: XYZ/DASds
X-MS-Exchange-MessageSentRepresentingType: 1
Date: Mon, 7 Mar 2022 12:54:02 +0100
Message-ID:
    <123.eurprd08.prod.outlook.com>
References:
    <123.eurprd08.prod.outlook.com>
In-Reply-To:
    <123.eurprd08.prod.outlook.com>
Content-Language: pl-PL
X-MS-Has-Attach: yes
X-MS-TNEF-Correlator:
X-MS-Exchange-Organization-RecordReviewCfmType: 0
Content-Type: multipart/mixed;
    boundary="_002_VI1PR0802MB2255D7C42F929D70566E9C7982089VI1PR0802MB2255_"
MIME-Version: 1.0

--_002_VI1PR0802MB2255D7C42F929D70566E9C7982089VI1PR0802MB2255_
Content-Type: text/html; charset="iso-8859-2"
Content-Transfer-Encoding: quoted-printable

some html content

--_002_VI1PR0802MB2255D7C42F929D70566E9C7982089VI1PR0802MB2255_
Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;
    name="some_file.xlsx"
Content-Description: some_file.xlsx
Content-Disposition: attachment; filename="2022_03_04.xlsx"; size=41422;
    creation-date="Mon, 07 Mar 2022 09:57:43 GMT";
    modification-date="Mon, 07 Mar 2022 12:08:34 GMT"
Content-Transfer-Encoding: base64

contents of attached file

--_002_VI1PR0802MB2255D7C42F929D70566E9C7982089VI1PR0802MB2255_--
52
0 + 0
Appleoddity avatar
ng flag
Appleoddity
A typical NDR contains more information than this. This isn’t enough information to even determine if it is on your end or theirs. It definitely isn’t something that would be received from Office 365 which is far, far, more detailed. Why do you think the problem is on your end as opposed to theirs? If this is all the information they get on their end then it’s 100% on their end.
0
Reply
us flag
DonCziken
@Appleoddity - to be fair I was assuming that the problem is on their end -as they are the only one to complain about delivery, all other clients/partners/etc are able to reach the e-mail properly. However as stated above sending exactly same e-mail from their servers is reaching google and few other major players, the problem is only when dealing with o365. Therefore I thought there might be some option to figure out whats going on on receiver end.
0
Reply
us flag
DonCziken
Whats more they can send same message towards other o365 hosted e-mails (I've personally tested with other domain and it worked like a charm).
0
Reply
Score:0
avatar Server
us flag
DonCziken

In the end problem turned out to be Outlook client. Person who was trying to send e-mails with attachments in addition to his (the problematic one) e-mail had also configured MS exchange account from the domain where the mails were being send to.

Such setup caused that the contact list was pooled and synced from MS in theory only for the account from problematic domain, but when he was trying to send e-mail from other account the list from MS exchange was still available and when selected it did not contain the full address, basically ending up with sending e-mail without the to email i.e. to='John Doe' instead of to='John Doe john.doe@example.com'.

0 + 0
ธงชาติไทย
Elon Musk
I sit in a Tesla and translated this thread with Ai:

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.