When a visitor visits the site canyouseeme.org and type in a port number, let's say 80 for example, (IP is already detected by canyouseeme), would that be equivalent to do the following telnet:
telnet <ip-detected-and-reported-by-canyouseeme> 80
In my case, canyouseeme can see the service on my IP on the specified port, but telnet says that the connection is refused and unable to connect.
Why the difference?