What port should be listening before a successful connection is possible?

CORRECT TEXT
An administrator is configuring a secured webserver, however connecting to https://127.0.0.1
is not working. The administrator runs netstat -ntl, which returns the following output: tcp 0 0
0.0.0.0:80 0.0.0.0:* LISTEN What port should be listening before a successful connection is
possible? (Provide only the numerical value of the port).

Answer: 443