Incoming mail from MSN/Hotmail

I am experiencing a problem receiving mail into my server from MSN/Hotmail. I sent test messages from my hotmail account, and I did receive a "delayed" message, but I am waiting for the official bounce so I can see what might possibly be the problem.

I did note that the server that sent the "delayed" message was listed on the spam.dnsbl.sorbs.net spamlist, but I do not have sorbs.net listed in my MAPS list. I currently only use the following:

bl.spamcop.net
sbl.spamhaus.org
list.dsbl.org
dnsbl.njabl.org
dynablock.njabl.org

I checked each of those sites and the IP was not listed at any of these sites. I also found a list of msn/hotmail mailserver IPs, so I whitelisted those, but yet mail is still not getting through from MSN/Hotmail to my VPS.

Again, I am still waiting for an official bounce message so I can see what the error is, but was wondering if anyone else was experiencing this problem or maybe had a idea on how to get mail coming from msn/hotmail again.

Thanks