From: ASundstrom on
I found that when I tried to log into the Central Administration site on the
SharePoint application server that I received multiple user prompts, followed
by a failed authentication with 401 1 3221225581 0 errors in the IIS logs.
We have NTLM configured for SharePoint, SSL forced and use an ALIAS for the
sites.
I found the following link, which helped me come to the conclusion that it
had something to do with NTLM. I had run into a similar problem trying to
use SharePoint on an NLB and found the following link and information which
fixed my problem, so I thought I would share.

A. Disable Loop Back Checking for the ALIAS
1. You may experience this error in the IIS logs “401 1 3221225581 0”
2. http://support.microsoft.com/kb/896861
3. Click Start, click Run, type regedit, and then click OK.
4. In Registry Editor, locate and then click the following registry key:
5. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
6. Right-click MSV1_0, point to New, and then click MultiString Value.
7. Type BackConnectionHostNames, then press ENTER and input the different
FQDN's that you will be using.
7.1. IE – admin.sharepoint.dot.nc.net
8. Quit Registry Editor
9. Try navigating the site and see if it tries to re-authenticate.