I have configured saml in aem 6.3 following this documentation, http://www.aemstuff.com/blogs/july/saml.html
It is working fine in publish, but in author I am getting below exception some times and login fails.
12.06.2018 10:39:13.096 *ERROR* [qtp45451009-84563] com.adobe.granite.auth.saml.util.SamlReader Document is invalid: no grammar found.
12.06.2018 10:39:13.096 *ERROR* [qtp45451009-84563] com.adobe.granite.auth.saml.util.SamlReader Document root element "Response", must match DOCTYPE root "null".
and in the page it shows,
This page contains the following errors:
error on line 1 at column 1: Document is empty
Below is a rendering of the page up to the first error.
Anyone faced similar issue? Please advice?