Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Dear anne baker1
Good day!
Thank you for posting to Microsoft Community. We are glad to assist!
For the known issue of sending to Yahoo emails, I have asked my consult team, currently Microsoft is still working on this, and no ETA. As we are moderator in Community, we are not authorized to check the details with the product team, but we will update you as soon as we get the latest information. Thanks a lot for your understanding and patience!
At the same time, I did some research in the forum and found in some similar threads, the issue can be fixed by adding SPF, DKIM, DMARK records. Please refer to the threads below and hope they can be helpful:
Authenticate Outbound Email to Improve Deliverability - Microsoft Community Hub.
Thanks for your precious time and your understanding would be highly appreciated. Have a nice day!
Best regards,
Allen | Community Moderato