What about your exim log ? when you send to hotmail account do you get " 220 code + Queued for delivery" but never delivered ?
If this is the case fill in this form :
https://support.live.com/eform.aspx?prod...mts&scrx=1
If this is the case fill in this form :
https://support.live.com/eform.aspx?prod...mts&scrx=1