Docker installation in Plesk with Nginx reverse proxy

I am trying to install docker for grafana-oss (8.3.4) in Ubuntu 20.04 server with Plesk Obsidian (18.0.40). As required, I use the following env settings for docker run:

docker run -d -p 3000:3000 --name=grafana -v grafana-storage:/var/lib/grafana -e "GF_SERVER_PROTOCOL=https" -e "GF_SERVER_DOMAIN=mydomain.com" -e "GF_SERVER_CERT_FILE=/var/lib/grafana/fullchain1.pem" -e "GF_SERVER_CERT_KEY=/var/lib/grafana/privkey1.pem" -e "GF_SERVER_ENFORCE_DOMAIN=true" -e "GF_USERS_ALLOW_SIGN_UP=false" -e "GF_AUTH_ANONYMOUS_ENABLED=false" grafana/grafana-oss

I have also configured Nginx conf like this (ref url://grafana.com/tutorials/run-grafana-behind-a-proxy/):

map $http_upgrade $connection_upgrade {
  default upgrade;
  '' close;
}

server {
  listen 80;
  root /usr/share/nginx/html;
  index index.html index.htm;

  location / {
    proxy_pass http://grafana.staged-by-discourse.com/;
  }

  location /api/live {
    rewrite  ^/(.*)  /$1 break;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection $connection_upgrade;
    proxy_set_header Host $http_host;
    proxy_pass http://grafana.staged-by-discourse.com/;
  }
}

I also copied and verified that the cert files (fullchain1.pem and privkey1.pem) are inside the docker in the mentioned path via docker inspect grafana and using docker exec -it <container_ID> /bin/bash.

I am however ending up with server.go:3160: http: TLS handshake error: EOF

How should I go about getting my installation right?