firewalld has 443 enabled but it refuses connections

The error Connection refused usually means the firewall allowed the packets to get through (unless the firewall is actively rejecting the connection attempt), but there is no service listening on the destined port number.

In your case, you need to make sure an HTTPs web server is running and listening port 443. You can use the following command to verify.

sudo netstat -lnp | grep 443

Edit: As commented by @Paul, the shown output means there is no process listening on port 443. The output is irrelevant because the process ID matched 443 and we need it to match with port number of TCP protocol. You need to find a line similar to:

tcp  0   0*     LISTEN      <pid>/<proc_name>