I am working for a company that sent marketing emails campaign.

We have delivery issues specially for one of our customer on hotmail domain. When testing email campaign, we do not receive the email in our hotmail test account. Nor in the inbox nor in the spam folder. 

In our MTA server log, we can see that the message was delivered to hotmail server ! Where are our emails ? 

We already support every recommendations to allow good email delivery (Sender-ID, DKIM,...). We also check SNDS IP status and it is bad ! How can we check the real reason of undeliverability of our messages ?

Is there any other stuffs that we could use to find the problem we have with hotmail ? 

We sent also other campaign with other IP and servers and we do not have any problems with them ! 

Regards.