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error message "Your message wasn't delivered. Despite repeated attempts to deliver your message, a connection to the remote server was closed abruptly.
Contact the recipient by some other means (by phone, for example) and ask them to tell their email admin that it appears that your email system is unable to connecto their email system. Give them the error details shown below. It's likely that the recipient's email admin is the only one who can fix this problem.
For Email Admins
This often indicates the recipient's firewall SMTP fixup setting or other firewall settings are preventing the SMTP protocol negotiation from succeeding.
For more information and tips to fix this issue see this article: https://go.microsoft.com/fwlink/?LinkId=389361.
For Yahoo: returned '550 5.4.318 Message expired, connection reset (SuspiciousRemoteServerError)(450 4.4.318 Connection was closed abruptly (SuspiciousRemoteServerError))'
3/8/2024 8:44:42 PM - Server at mx-eu.mail.am0.yahoodns.net (188.125.72.73) returned '450 4.4.318 Connection was closed abruptly (SuspiciousRemoteServerError)'
For sky: returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to SocketError'
3/8/2024 8:39:33 PM - Server at 188.125.72.73 (188.125.72.73) returned '421 4.4.2 Connection dropped due to SocketError'
I cannot ask all my contacts that have yahoo or sky accounts to change their firewall settings. There seems to be a problem with Microsoft!
Sending, receiving, and organizing email in Outlook on the web for business
Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.
Unfortunately, this information is absolutely not helpful for those of us who are not IT professionals to understand what needs to be done to solve this issue.
Dear Admin Act for Inclusion,
Thank you for visiting Microsoft Community, we are glad to assist you here.
Please kindly note this is a known issue as Yahoo made an authentication change, requiring email senders to strongly authenticate their emails following well-established best practices such as DMARC, SPF, and DKIM.
Please follow the steps to enable it as below:
Set up SPF identify valid email sources for your Microsoft 365 domain | Microsoft Learn
How to use DKIM for email in your custom domain | Microsoft Learn
Use DMARC to validate email, setup steps | Microsoft Learn
Email authentication in Microsoft 365 | Microsoft Learn
For your reference:
Authenticate Outbound Email to Improve Deliverability - Microsoft Community Hub
If still same issue, it is suggested to open ticket and contact Microsoft Technical team Get support - Microsoft 365 admin | Microsoft Learn to get further assistance on this query.
Thank you for your time.
Please feel free to get back to us if you have further concerns,
Regards,
Microsoft Community
DMARC record and SPF simply wasn't enough...had clients who had this in place and they started getting rejections last week. DKIM is now needed to send to ATT/Yahoo/Sbcglobal addresses...their guidelines should be updated: https://senders.yahooinc.com/best-practices/
I am having the same issue with yahoo, aol, and rocket mail email addresses!
Hello
Good day.
Thank for posting in the community.
We've received your query and you can expect to receive response from one of our community moderator accordingly.
At this point, we appreciate your patience and cooperation. Thank you.
Sincerely,
Community moderator
This morning I received calls from 3 clients with the same issue.