A client is sending us an email from their Hotmail address (upgraded to Outlook.com) but it is not arriving. They are using Hotmail through their web browser on a Mac.

Their emails get sent with no errors and arrive in other inboxes (Hotmail, xtra.co.nz) but not our company inboxes (Outlook Server 2010).

We see no trace of these emails hitting our email gateway (MailMarshal).

Emails from other Hotmail accounts arrive in our company inbox fine (such as my hotmail address).

Do you know why this is happening ?

Do you know why there is no error or bounce back on the Hotmail side ?