Hi @ADITYA_SHARMA2,
when I am running the web framework on my localhost with this connection string it is running properly, but when I am hosting it on the vpc it showing the error.
Have you attempted to connect without the use of VPC peering from the VPC where your app is hosted as suggested in my previous comment? Please also try the standard connection string to see if you are able to connect.
Additionally, from the client hosted on your VPC, please try to run some network troubleshooting steps such performing a ping and telnet against one (or all) of the node(s) within the cluster using their hostname(s). Please provide the output of those tests here. You can refer to my comment in this post regarding how to find the hostnames of the nodes within your cluster.
Regards,
Jason