Cant connect to server (Port forwarding issue?)

When I have the server on the port 25565 I can connect to the server but my friends can’t. I tried changing the port to 25563 so I went to “server-port=” and changed it. But when I do that, they cant connect to the server and I can’t either. I really need help.
Edit: I also went into my router settings and changed it to 25563 and I still can’t connect.