Requirement:- We have Apache server on the top of a tomcat container where we have deployed application Webnow. This application will provide SSO to another application Imagenow. The requirement is we have to authenticate and authorize a user based on the client certificate which will be installed on the client side browser. Issue:- We have achieved the requirement for the browser IE. But for browser Firefox ,we are getting an exception "Class not found". Basically an applet class from the jar is not getting loaded on the Firefox. Further investigating on this we came to conclusion that Firefox is not able to read the SSL certificate. In order to eliminate this, we have imported the client certificate in java console as well. After this step, we were not getting "ClassNotFoundException" in FF. But right now, user is getting prompted for certificate/keystore password each & every time while trying to login onto the application (both in IE & FF). So, we are trying to find ways to remove class not found exception without importing client certificate to java console. Also , is there any way to eliminate the authentication pop up for keystore (though we might not go for this approach as it will be very difficult to manage Java console for end users). Need your urgent help on this issue. Attaching stack trace of both the browser and screenshot of keystore authentication pop-up . FF_Issue_stacktrace.docx is one when we were getting "class not found exception" and IE_Stacktrace.docx is one for successful case.