Nginx HTTPS connection to port 443 refused

So I've setup LetsEncrypt on my Nginx server but cannot connect over https. If I run

curl https://my.domain.com

Then I get the error

curl: (7) Failed to connect to my.domain.com port 443: Connection refused

So for some reason my Nginx server is not listening on port 443. If I run 'sudo netstat -anltp' then I can definitely see this

tcp        0      0 0.0.0.0:4747            0.0.0.0:*               
LISTEN      16145/sshd      
tcp        0      0 0.0.0.0:111             0.0.0.0:*               
LISTEN      155/rpcbind     
tcp        0      0 0.0.0.0:80              0.0.0.0:*               
LISTEN      15413/nginx: master
tcp        0      0 0.0.0.0:25              0.0.0.0:*               
LISTEN      507/master      
tcp        0      0 168.235.68.234:4747     204.148.137.74:10163    
ESTABLISHED 17096/0         
tcp6       0      0 :::4747                 :::*                    
LISTEN      16145/sshd      
tcp6       0      0 :::111                  :::*                    
LISTEN      155/rpcbind     
tcp6       0      0 :::80                   :::*                    
LISTEN      15413/nginx: master
tcp6       0      0 :::25                   :::*                    
LISTEN      507/master     

My sites-available config file:

server {

    listen 443 default_server ssl;
    listen [::]:443 default_server ssl;

    root /var/www/my_domain/html/;
    index index.html index.htm index.php;

    server_name my.domain.com;

    ssl on;
    ssl_certificate /etc/letsencrypt/live/my_domain.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/my_domain.com/privkey.pem;



    location / {
            root /var/www/my_domain.com/html/;
            index index.html index.php;
    }

    location /robots.txt/ {
            root /var/www/my_domain.com/html/robots.txt;

    }

    location /.well-known/acme-challenge {
            root /var/www/letsencrypt;
    }

My Nginx.conf :

worker_processes  1;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;

load_module /etc/nginx/modules/ngx_http_fancyindex_module.so;
events {
    worker_connections  1024;
}

http {
    include       mime.types;
    include /etc/nginx/sites-enabled/*;
    default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] 
"$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;

server {
        listen       80;
        server_name  localhost;

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
            root   html;
            index  index.html index.htm;
        }

        #error_page  404              /404.html;

        # redirect server error pages to the static page /50x.html
        #
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
   }

# HTTPS server
    #
    #server {
        #listen       443 ssl;
        #server_name  localhost;

        #ssl_certificate 
/etc/letsencrypt/live/my.domain.com/fullchain.pem;
        #ssl_certificate_key  
/etc/letsencrypt/live/my.domain.com/privkey.pem;

        #ssl_session_cache    shared:SSL:1m;
        #ssl_session_timeout  5m;

        #ssl_ciphers  HIGH:!aNULL:!MD5;
        #ssl_prefer_server_ciphers  on;

        #location / {
            #root   html;
            #index  index.html index.htm;
        #}
    #}


}

My UFW Status :

To                         Action      From
--                         ------      ----
22                         DENY        Anywhere                  
4747                       DENY        Anywhere                  
80                         ALLOW       Anywhere                  
443                        ALLOW       Anywhere                  
22 (v6)                    DENY        Anywhere (v6)             
4747 (v6)                  DENY        Anywhere (v6)             
80 (v6)                    ALLOW       Anywhere (v6)             
443 (v6)                   ALLOW       Anywhere (v6) 

Hopefully my two conf files aren't too much of a mess. If anyone has any ideas on why port 443 is being rejected I'd appreciate it. I thought maybe it might have something to do with the location of my .key files but wasn't sure on that. Also running 'nginx -t' works with no errors.

Also yes I'm aware that this post NGINX won't listen on port 443 exists but it was voted 'off topic' because the creator abandoned the post and so no solution was ever found.