When attempting to start the DRA App Pool in IIS and access the DRA Web site, the following entries may appear in the Application log due to the App Pool not starting:
The Module DLL 'D:\Program Files\Microsoft\Exchange Server\V14\Bin\kerbauth.dll' could not be loaded due to a configuration problem. The current configuration only supports loading images built for a x86 processor architecture. The data field contains the error number. To learn more about this issue, including how to troubleshooting this kind of processor architecture mismatch error, see http://go.microsoft.com/fwlink/?LinkId=29349.
You may also see this entry in the System log:
A listener channel for protocol 'http' in worker process '7336' serving application pool 'DRAAppPool' reported a listener channel failure. The data field contains the error number.
<filter name="Exchange ActiveSync ISAPI Filter" path="D:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\sync\bin\AirFilter.dll" enabled="true" preCondition="bitness64"/>
Under GlobalModules make sure you have the following line:
<add name="kerbauth" image="D:\Program Files\Microsoft\Exchange Server\V14\Bin\kerbauth.dll" preCondition="bitness64" />
When you load DRA Web console you will get an error message about it not being able to load a DLL Find that DLL in the applicationHost.config file and add the preCondition="bitness64" to it. Then, restart IIS.