Hello Everyone,
Sometimes this issue can be caused by your trusted sites. ArcGIS Catalog will respect the WinInet Options. I suggest adding the following lines to your trusted sites:
*note: If you can, uncheck the box that states 'Require Server Verification...'
Go to Internet Options > Security > Trusted Sites and select the 'Sites Button'
Add the following URLS:
http://www.arcgis.com
http://*.arcgis.com
This will correct this issue for some customers. You can use web debugging tools, such as Fiddler, to troubleshoot these kinds of issues as well.
I hope this helps. Thank you very much-
Justin
Esri Support