We have Microsoft Office 365 as our email provider. A good amount of people sending from Yahoo based email accounts (including those who lease yahoo servers) cannot send to us. They sometimes get a bounce back message which I have attached. I am looking for any assistance as Microsoft and Yahoo are extremely difficult to get support from. The error message in the bounce back comes from Yahoo's Mailer Daemon, and tries several times to send.
This may be impossible to get.
You'll have to look for either raw SMTP log access in your Microsoft Office 365 account or open a trouble ticket with Microsoft Office 365 asking for the SMTP information.