Remote Server returned '554 5.4.0'

Question

Hi All, One of my user is facing issue sending email to an external domain user. he is getting the below NDR. is anything to look at my end or its an issue at the recipient domain end.

Delivery has failed to these recipients or groups:

user1@somedomain.com
A problem occurred during the delivery of this message. Please try to resend the message later.

Diagnostic information for administrators:
Generating server:
user1@somedomain.com
Remote Server returned '554 5.4.0'

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Your message did not reach some or all of the intended recipients.
Subject: TEST
Sent: 2/20/2021 08:00 PM
The following recipient(s) cannot be reached:
user1@somedomain.com on 2/24/2021 10:13 PM
None of your email accounts could send to this recipient.

Answer 1

@Glenn Maxwell

The "554 5.4.0" error is related with too many hops. If there exist such issue, it will effect all mailboxes rather than only on mailbox. So, I would suggest you provide a screenshot about the information in that NDR(remove domain name from it), it will help us to narrow down this issue.

If this mailbox could send emails to other mail servers, it means this issue related with the MX record for target mail server, you need to contact target mail server administrator.

If you organization cannot send emails to other mail servers, you can take steps below to solved this issue:

1. If you are using Exchange online, just delete/disable all connectors on Exchange online.
2. If you are using Exchange on-premises, delete/disable all send connectors, then recreate a new with this article.
3. If you are using hybrid, delete all connector from Exchange online, remove send connector from Exchange on-premises, then rerun HCW to recreate them.

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Answer 2

Delivery is delayed to these recipients or groups:
'Aaaaa' (wxxxx@gmail.com)
Subject: test 14
This message hasn't been delivered yet. Delivery will continue to be attempted.
The server will keep trying to deliver this message for the next 1 days, 19 hours and 52 minutes. You'll be notified if the message can't be delivered by that time.





Diagnostic information for administrators:
Generating server: CAS1.aaaaa.com.pk
Receiving server: gmail.com (2404:6800:4003:c00::1a)
wxxxx@gmail.com
Server at gmail.com (2404:6800:4003:c00::1a) returned '400 4.4.7 Message delayed'
2/14/2023 1:30:26 PM - Server at gmail.com (2404:6800:4003:c00::1a) returned '451 4.4.397 Error communicating with target host. -> 421 4.2.1 Unable to connect -> SocketError: Failed to connect. Winsock error code: 10051, Win32 error code: 10051'
Original message headers:
Received: from DESKTOPNVS1LO2 (192.168.0.0) by CAS1.aaaaa.com.pk
 (192.168.0.xx) with Microsoft SMTP Server (version=TLS1_2,
 cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2375.28; Tue, 14
 Feb 2023 14:33:11 +0500
From: <ww@aaaaa.com.pk>
To: 'w' <wxxxx@gmail.com>
Subject: test 14
Date: Tue, 14 Feb 2023 14:33:39 +0500
Message-ID: <000001d94057$6bb29b60$4317d220$@asktech.com.pk>
MIME-Version: 1.0
Content-Type: multipart/alternative;
	boundary="----=_NextPart_000_0001_01D94081.5488A360"
X-Mailer: Microsoft Outlook 16.0
Thread-Index: AdlAV2fbjj3pcbIGQryaksDKTkT7Cg==
Content-Language: en-us
Return-Path: wx@aaaaa.com.pk
X-Originating-IP: [192.168.0.0]

Answer 3

If it is happening in Outlook Client, you can try to clear the Auto-Complete List and then open the Outlook in Safe mode. Try sending the mail again.