Something horrible happened. If the below message states that the SAML 2 SSO Profile is not configured for you, then either you haven't uploaded your metadata yet or your SP's entityID has not yet been properly configured.

If your message did not meet security requirements, ensure that your SP's clock is accurately set and that you're not using the back button during the authentication process.

For more information, you can check out the IdP's error log.

The Common Errors page for the IdP at the Shibboleth Wiki may help you debug the problem.

Error Message: Message did not meet security requirements