Kindly ensure whether the DSC is installed in the machine :
(Steps to check the DSC : Go to Internet Explorer --> Click on Tools --> Internet Options --> Click on the Content tab --> Click on Certificates -->Check for your installed DSC in the Personal tab.)
Go to Control panel --> double click the java icon -->
Click on Security tab -->
Select ‘High’ --> Click on ‘Edit Site List’ and add URL (https://onlineservices.tin.nsdl.com/TIN/JSP/security/Login.jsp) in exception site list --> OK (For JAVA above 1.8 update 20 version (32-bit version) )
Click on General tab -->
Click on settings -->‘Delete Files’ then enable all the options --> OK
Click on Advanced tab -->
Enable the settings Use SSL 3.0,Use TLS 1.0,Use TLS 1.1,Use TLS 1.2 --> Apply --> OK.
Click on Update tab -->
Uncheck the option check for updates automatically --> pop up message will appear i.e. check for monthly or do not check, click on do not check option & proceed further.
Go to Internet Explorer --> Click on Tools --> Internet Options -->
Click on General tab -->
Click on settings --> click on view files --> select & delete all the files.
Click on Advanced tab -->
Enable the settings Use SSL 3.0,Use TLS 1.0,Use TLS 1.1,Use TLS 1.2 --> Apply --> OK.
Reopen Internet explorer and then try registration.