Issues configuring TLS 1.2 on Shiny Server Pro

I have SSL cert installed on my server, am trying to change the default TLS to 1.2 as it is more secure, but whenever I add the following line in the config file under Server the server becomes unreachable:

server {
listen 443;
ssl /etc/shiny-server/key.pem /etc/shiny-server/cert.cert;
ssl_min_version tlsv12;