Please use latest ms excel,emsigner.before trying to sign a prompt appears in explorer...There u need to allow blocked contents.
If anything is not working try ERP CLOUD ANALYSIS website to sign form 9c
Download the latest version of emsigner. Install the emSigner after downloading it.. Open the GSTR-9C Offline Utility Excel Worksheet > Include the table-wise details in the Worksheet > Create Preview PDF file > Access the Draft Form GSTR-9C.Create JSON File which auditor will attest by affixing his/her DSC.