And if you are using OctoPi (which you haven't specified but is the most common form) it'll have to be 80 because 5000 is not open on the network.
In general I'd advise you @roland78 to be a bit more forthcoming about your setup here because right now it's pretty much impossible to help you considering that we no pretty much nothing but "can't connect from Cura". To what version. How installed. On which kind of network setup. Etc etc. Information. We need it.