FolderSync Failed - ActiveSync
If you are running the TestExchangeConnectivity.com test and pass the OPTIONS test but then fail the next FolderSync test, you may pull your hair out going over every detail of an already immaculate configuration. There's one thing you might not do, given that it's not in most common ActiveSync troubleshooting guides.

1. Run the IIS Manager tool

2. Get properties on "Default web site".

3. On the Web Site tab, click Advanced

4. In the "Multiple identities for this website" area, click on the default entry and choose Edit

5. Make these changes - IP address: (All Unssigned), TCP port:80, Host Header Value: empty

6. Click OK to close out.

7. Restart the IIS Admin Service.

Now go and test again and see if this was your silver bullet.  ¶ 2:14 PM