Looks to be working now, your existing certificate only covers riramakrishnahospital.com though, so you would want to add testipnew.sriramakrishnahospital.com to that certificate or create a new certificate just for that subdomain. Certificates have to either mention the full website domain (including subdomains like www etc) or be a wildcard (e.g. *.sriramakrishnahospital.com)
we tried again today. but no luck. the same error shows again. Sorry the subdomain we trying to install SSL is given below testingip.sriramakrishnahospital.com
So, it will only be possible to obtain a cert for that name via DNS-01 authentication; As HTTP-01 authentication challenges require routable IP addresses.