Can't log in as SSO Admin

vSphere 5.1.  I can't log in as admin@System-Domain on vSphere client or Web Client.

I do know my password, and I can correctly authenticate from command line "rsautil reset-admin-password" as described here:

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2034608#5.1

But from vSphere client or Web Client it is a "Provided credentials are not valid." every time.  Is there something obvious I am missing?

Thanks,

Jaime