We have a FE and BE Exchange 2003 server in our organization. Both have SP2 installed and we have mobile users using Iphones . We have configured Active Sync on exchange server. However, the issue is the delivery of the emails is not instaneous. It takes sometimes 15 minutes for the emails to get delivered. If the end user opens the mail app on the iphone, then the emails are delivered right away. Can somebody point me in the right direction ? Its not that the emails are not getting delivered at all, its just that they are taking considerably longer .