There are numerous issues that can cause this to occur (Usually a full page).
Check the following:
Check to see if your SSL Cert is Expired
If your Redirect is on
If this is all okay, then your Java may be out of date. Strongly suggest The Latest version and reinstalling it.
What Current Version of Java works with Docstar
REdirect Tomcat to point at the right Java installation.
You can follow the steps in this Article to help you point Tomcat and restart the services.
Pointing Tomcat at the Right version Of Java