The Manager displays a white screen and Fiddler will return 500 errors. Browsing to localhost/Geocortex/IdentityServer (otherwise just a blank screen was displayed) returns Error calling loadlibraryex on isapi filter "c:\windows\microsoft.net\framework\v4.0.30319\\aspnet_filter.dll" failed.
To resolve, follow the steps below:
1. Click on your computer icon in IIS
2. Select ISAPI filters
3. Notice the filter name ASP.Net_4.0_64bit %windir%\Microsoft.NET\Framework64\\v4.0.30319\aspnet_filter.dll
4. Remove the extra slash after Framework64
4. Restart the Manager