shibd.log is blank when testing IdP at sp.testshib.org

[Khawer Masood]

Upon testing an IdP at https://sp.testshib.org/ <https://sp.testshib.org/>, the exception below appears, but shibd.log is blank. Any ideas on what might be happening? The authentication succeeds, but not errors are logged on IdP side. Relevant versions are: Shib v 3.1.1, OEL 6.6, Jetty 9.2, Oracle JDK 1.8.0_45. 

Thanks,

KM

Exception is:
I'm sorry this didn't work out just yet.

opensaml::FatalProfileException at (https://sp.testshib.org/Shibboleth.sso/SAML2/POST)

Unable to establish security of incoming assertion.
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