Detected a problem with assertion: Unable to establish security of incoming assertion.

[Peter Schober]

* kripp <kripp at compsych.com> [2014-12-01 15:29]:
> initiated POST binding.  I am seeing the following error in our logs "WARN
> Shibboleth.SSO.SAML2 [1]: detected a problem with assertion: Unable to
> establish security of incoming assertion."

Documentation -> Troubleshooting -> Native SP: Common Errors
Third entry on that page.

(I know that only tells you to look at your shibd.log for specifics, but
now you know where to look for explanation of other error messages
too.)
-peter