Mails from microsoft exchange email services are failed in plesk (qmail). Upon investigation we found that the grey list filter in plesk 10 is blocking server that are on “dsl|pool|broadband|hsd” address ranges. In this case it would be Microsofts cloud anti-spam service that is on “pool” addresses.
Some Microsofts cloud anti-spam servers are;
co9outboundpool.messaging.microsoft.com db8outboundpool.messaging.microsoft.com db9outboundpool.messaging.microsoft.com am1outboundpool.messaging.microsoft.com
Log entries are like this