Using Classic Outlook on Windows for personal email, calendar, and contact management
The problem is almost certainly in the DNS configuration of their personal domains.
This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
getting these two error messages when sending to yahoo
1/11/2024 3:34:15 PM - Server at DS0PR14MB7526.namprd14.prod.outlook.com returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to SocketError'
1/11/2024 3:24:36 PM - Server at PH0PR14MB6715.namprd14.prod.outlook.com returned '550 5.4.300 Message expired -> 421 4.4.2 Connection dropped due to ConnectionReset'
Using Classic Outlook on Windows for personal email, calendar, and contact management
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.
The problem is almost certainly in the DNS configuration of their personal domains.
I use a yahoo account and this just started over the last 3 weeks. It was never an issue. However, both of the people emailing me are using personal domains and the emails are bouncing back to them saying I have the Microsoft issue.
If you use custom domain and your mail related DNS records are either missing or incorrect, you will have the same problem. It will never go away unless you fix the problem yourself.
I am having the same thing and don’t use Microsoft 365
There are 2 issues that I know at this time:
You are responsible for #1. Microsoft can't fix the problem for you.
#2 (Microsoft IP addresses blacklisted on many DNSBL database) is Microsoft's responsibility.