After upgrading Jaspersoft from 6.3 to 6.4.2 the login button is grayed out.
This was also after putting all customizations and changes back into place.
This was seen due to using the web.xml file from the 6.3 installation in 6.4.2.
The issue goes away when putting the 6.4.2 web.xml file in place.
All settings will have to be redone after upgrade.