emails are bouncing back when sending to yahoo

I have owned a travel agency for 23 years and off and on this has been an ongoing problem. Most of the time I can tell my clients to look in their spam/junk folder and my emails are sitting there. Now they are no where to be found. I actually did a search on Microsoft and found people asking the same questions on how to fix this as far back as 2013....I stopped looking after that. I guess until they resolve this issue once again I will have to send emails from a Gmail account to get around this. But you would think as big of a company as Microsoft that they could resolve this quickly with the $$$$ they have to hire the best IT people.

Hi Ankita,

I have done the things you mentioned above and the problem still has not be solved. Can you give us some information as to what is the issue with Microsoft and yahoo and when you project the problem will be solved.

thank you!

Hi Ankita,

We are now receiving this error message:

Remote server returned '550 5.4.300 Message expired -> 451 [RL01] Message temporarily deferred'

please advise!

My entire domain of 100 users cannot send to anyone at Yahoo Mail. We use Microsoft 365. The message attempts to be delivered for several days then returns:

Message expired -> 421 4.4.2 Connection dropped due to SocketError'

1/13/2024 4:49:09 AM - Server at mta6.am0.yahoodns.net (98.136.96.91) returned '421 4.4.2 Connection dropped due to SocketError'

I'm having the same issue only for my users it is yahoo, aol, and frontier and it's ONLY when they reply to an email sent to them by the recipient.