FAILED TO DOWNLOAD OUTLOOK ADDRESS BOOK (OAB) IN OUTLOOK CLIENT

Symptom

Some of users failed to download the Outlook Address Book from outlook client, the downloading process,  keep loading and take time to finish.

Cause

The downloading process failed from outlook client, because the Web Gateway blocked the access.

Resolution

The workaround, add the Exchange CAS name on the Exceptions list in the Internet Explorer Settings.

Troubleshooting steps:

Step 1:  Verify and check the OAB URL from the Outlook client, Test E-mail Autoconfiguration.  Uncheck the option "Use Guessmart" and "Secure Guessmart Authentication" and click Test.  Go to the XML tab and copy the OABURL, Example OAB URL path:

<OABURL>Http://cas_server_name.domain.com/0000000-0000-0000-0000/</oaburl> 

Step 2:  Copy the OABURL and paste the internet browser and edit the URL as example below and press enter;

Http://cas_server_name.domain.com/0000000-0000-0000-0000/oab.xml  

Step 3.  We should see the OAB content with combination word & number in encryption.  If you see the different page, such as Web Gateway as below;.  So we need to add the Exchange CAS name on the Exceptions list in the Internet Explorer Settings at every user that has the problem.