Summary

JIRA provides the Audience URL (Entity ID) to be used in the Identity Provider. The URL is given as https://jira.atlassian.com
When configuring the Identity Provider a user may enter a trailing / at the end of the URL such as :
https://jira.atlassian.com/

When JIRA checks for a valid Audience URL it will fail because of the trailing / and the error message is not clear that the / is causing the problem.

Expected Result

JIRA should check for a trailing / and remove it to allow it as a valid Audience or display a more specific error that the Audience is not valid because of a trailing /

Actual Result

JIRA will give the following error in the logs:

Received invalid SAML response: https://jira.atlassian.com is not a valid audience for this Response

This error isn't clear because typically a URL with a trailing / will function the same as one without.

A better error message would be:

Received invalid SAML response: https://jira.atlassian.com is not a valid audience for this Response.
Received SAML: https://jira.atlassian.com/
Expected SAML: https://jira.atlassian.com