iPhone 2.0 software: Troubleshooting iPhone or iPod touch Exchange ActiveSync "Push" issues

Resolution

Here are some possible solutions:

1. Have your Exchange Server admin set the server's heartbeat interval to 59 minutes. The heartbeat interval is how much time that iPhone calculates should pass between pings to the server.  Instructions on setting the heartbeat interval are in the "More Information" section of this Microsoft Knowledge Base article: http://support.microsoft.com/kb/905013.
2. When roaming between home and office networks with Wi-Fi enabled, "push" may stop working if your company's Exchange ActiveSync server has a different IP address for intranet and Internet clients. Make sure the DNS for your network returns a single, externally-routable address to the Exchange ActiveSync server for both intranet and Internet clients. This is required so the device can use the same IP address for communicating with the server when both types of connections are active. A workaround to avoid this issue is to disable Wi-Fi on the iPhone.
3. Exchange Server 2003 users should refer to this Microsoft Knowledge Base article: http://support.microsoft.com/kb/817379
4. In some cases when using both a POP account and an Exchange ActiveSync account, the POP account may stick in the "Checking for mail..." state. During this time, Exchange ActiveSync emails may not be pushed. To resolve this, while in the Mail application, hold down the Home button for 9-10 seconds until the Mail application disappears and you are returned to the Home screen.

To further troubleshoot Exchange ActiveSync "push" issues, refer to Chapter 1 of the iPhone and iPod touch Enterprise Deployment Guide.

To troubleshoot MobileMe "push" issues, refer to this article.