I’ve started getting this question on a regular basis, so I thought it was time to post the how-to for it. More and more people are beginning to use mobile devices that support Exchange ActiveSync, and it’s more than just the PocketPC crowd. SBS provides a self-signed SSL certificate for secure web transactions, and most devices will not recognize the self-signed certificate, so you have to install the certificate into the store on the device before ActiveSync will work with Exchange. But the issue is not limited to the self-signed certificates, either. Some third-party certificates are not recognized as valid by some devices and also must be installed in the certificate store on the device before ActiveSync will work.

While there are a few different ways to transfer the certificate to a mobile device, I have had 100% success with the following method each time I have used it. Hopefully it will be of use to you, whether you have the self-signed SSL cert from SBS or a third-party cert that is not recognized as valid by all mobile devices.

  1. From the computer you use to sync via cable with the mobile device, go to the login page of the Outlook Web Access or Remote Web Workplace page on your server (https://servername/exchange or https://servername/remote) with Internet Explorer.

  2. Without logging in, double-click on the yellow lock icon in the Status Bar at the bottom of the IE window.
  3. In the Certificate window that pops up, click on the Details tab.
  4. Click the Copy to File button to launch the Certificate Export Wizard.
  5. Click Next.
  6. Select DER encoded binary X.509 (.CER) and click Next.
  7. Click Browse and choose a location to save the file that you can easily find later (like C:\).
  8. Name the file with a .cer extension and click Save.
  9. Click Next.
  10. Click Finish.
  11. You should get a window that says the export was successful. Click OK.
    Copy the .cer file to your mobile device.

  12. On the mobile device, find the .cer file and click on it to install it into the certificate store. Click Yes to install the certificate.