Make Sure the following:-
1. You should open gstr 9c offline utility in MS office 2010 or above. (2007 also, though I am not sure) (Enable editing and Enable content)
2. Internet Explorer should have been installed. (Edge is not useful)
3. The OS should be windows 10
4. Java utility latest update should be installed.
5. EM signer downloaded form GST site (latest)
If first two conditions are met, while we click on Generate json button, the internet explorer shall be opened. (if not either IE may not be installed, or Enable content of excel may not be activated)
In internet explorer, There will be initiate signing button and open em signer button. Ideally initiate signing button will be enabled and open emsigner button will be disabled. If both button is enabled, you have to go internet explorer security settings and enable all setting related ActiveX (for security settings, click on the three dots at top right corner of IE, and select internet option)
Once ActiveX is enabled, and if click on Initiate signing, the second button "open emsigner" will be enabled. Before clicking on that, please make sure, emsignerGSTN.exe has been run as administrator. Otherwise, server1 object error will come.
If everything is correct, emigner will launch and you can sign the GSTR 9-C
Thank You
Rashid