I opened port 25374, this is eMule TCP port, then I use canyouseeme.org to check if it is really opened.

I got the weird problem :

when eMule is running, canyouseeme.org see my port. I got the message : "Success: I can see your service on xxx.xx.xxx.xx on port (25374) Your ISP is not blocking port 25374"

When I close eMule then check the port again on canyouseeme.org I got : Error: I could not see your service on xxx.xx.xxx.xx on port (25374) Reason: Connection timed out

But when I turn off the windows firewall I got a different error : Error: I could not see your service on xxx.xx.xxx.xx on port (25374) Reason: Connection refused

Can anyone please explain to me why it happened like that and how to make the port always opened ?

Thanks