If I use Windows live mail to reply to a message received from a specific address and send it via my Hotmail account I get the error below. If I reply to the message using Windows Live Mail but send it via my Gmail account it works. If I log on to the Hotmail account on outlook.com and reply to the message it works.

The problem seems to occur only when I use the combination of Windows Live Mail and Hotmail, and it has only happened with one specific address.