Submitted GSTR 3B, but didnt able to file it with DSC?

You ll reinstall the emsigner.... And try

Reinstall the eMsigner open it with administrator rights. update your internet explorer to the version above 10 and the try.

uninstall all other DSC Drivers
download the latest emSigner 2.6v and install it
run as admin
use chrome.. u must be able to proceed

Please wait till they fix the DSC problem and keep trying regularly , Everything in your pc is correct, GST helpdesk provide this options like emsigner reinstall / change browser/ change window / close then open emsigner / Just to pass our time, The real problem is in their own website , You can try all the above settings but it will never work till they fix problem in their own website .