Hostname is just like "github.com", the field is actually the URI of the subsonic server (i.e. https://github.com/subsonic/)

ui/dialogs/addeditserverdialog.go

@@ -101,9 +101,9 @@ func NewAddEditServerDialog(title string, cancelable bool, prefillServer *backen
 			serverTypeChoice,
 			widget.NewLabel("Nickname"),
 			nickField,
-			widget.NewLabel("Hostname"),
+			widget.NewLabel("Url"),
 			hostField,
-			widget.NewLabel("Alt. Hostname"),
+			widget.NewLabel("Alt. Url"),
 			altHostField,
 			widget.NewLabel("Username"),
 			userField,