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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.
Eleni - I am using Microsoft Office 2019 and your links only appear to refer to Microsoft 365 users.
Do you have any solutions for those of us who are not using Microsoft 365 AND are not IT professionals.
Your help will be greatly appreciated by a lot of us.
Thank you for providing the Microsoft guidance, but I don't think most personal and small business users of Microsoft would understand any of this. I was only able to get my email working to send to yahoo as I had additional guidance from GoDaddy. The SPF was already set up, I set up the DKIM and I could immediately send emails to yahoo. I then tried setting up the DMARC and this stopped my ability to send emails to yahoo, so I deleted it. Leaving it for the moment as it is working, but Microsoft and Yahoo etc need to take note that the changes they are introducing are excluding people from using emails and must be damaging many small businesses, charities etc.
Thank you. Please keep me posted.
Just to say I have checked and verified my MX, SPF and CName records in my domain host's DNS settings and they were all correct and matched what Microsoft requires. HOWEVER, I had not applied the DKIM outbound encryption which it seems Yahoo and AOL (both the same company) now require, as do Sky and also, it seems BTinternet too. This isn't a Microsoft problem, it is theirs, but in reality it's likely to be something all providers will be requiring in future to prevent or reduce SPAM and phishing attacks.
I have now applied DKIM encryption in my Microsoft email settings (as per their guide earlier), plus I have added the two extra CName records with my domain host's DNS settings and I am testing now, but my emails are definitely still working. I just need to verify Yahoo and AOL recipients etc get them too, which I believe they will now.
Sadly, this complexity is the price we all pay to protect ourselves from those who are less than scrupulous
So after multiple of our clients had this issue. We found that we needed to setup DARC and DKIM records to our client 365 tenants. Seems yahoo and aol have this setup on their end.
After setting up these records we been having successful emails go through to those domains