I have this message when logging on to Vcenter 5.1:
The authentication server returned an unexpected error: ns0:RequestFailed: Internal Error while creating SAML 2.0 Token. The error may be caused by a malfunctioning identity source.
There is an article about it: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2034798
But doesn't work for me. Didn't change anything on the config.
Do you have/had the same issue?