[Morphy99]

The default port is just a placeholder, you need to specify your port in the input field.
As mentioned by Hellow, make sure the web interface is enabled in transmission and you can open it in your browser.

Thanks both yes I have it connecting now. Had to put /transmission/ in rpc URL. Maybe its because I'm running the dark theme it looked like I had already set the port. Maybe you could look at changing the placeholders to be a different font colour or next to the field instead of in it? Would save some silly confusions