smtp;554 The mail could not be delivered to the recipient because the domain is not reachable

I am a server administrator  and have a client with website and domain hosted with our company.  They have clients with windows live email and outlook.com email.  when a client trys to email them the email address turns read and when sent it gets returned.  we have isolated this problem to Microsoft.  the problem does not happen  when mail is sent to the client from gmail or any other email provider. the problem only happens on Microsoft web based mail. Here is the email that is sent back when the client sends an email to this one domain on our server.