Strangely seeing nginx welcome page on http with letsencrypt

Check if you have a ssl.conf file in /var/www/yourdomain.com/conf/nginx/

   listen 443 ssl http2;
    ssl on;
    ssl_certificate     /etc/letsencrypt/live/yourcert;
    ssl_certificate_key    /etc/letsencrypt/live/yourcert;`

And force ssl with with a file yourdomain-force-ssl.conf in /etc/nginx/conf.d/

	server {
	listen 80;
	server_name yourdomain.com;
	return 301 https://yourdomain.com$request_uri;
}