No windows when running through VNC

[Mighty M]

When I VNC to my RPi3 I can't see any qt windows from my App. The QT creator GUI displays fine. Its just my App that has no windows, running from QT Creator or the linux shell (LX terminal) there is no app GUI, it still doesnt display even if I run with the recommended Qt Creator Build and Run command line app argument :

-platform vnc:size=272x480

I get this printed out when I run from Qt creator (not from the shell) on VNC,

"VncServer could not connect: "The bound address is already in use"

So is there a way to run across VCN with a QT app ?

[Kent-Dorfman]

and what happens when you run creator and your app on a real computer? are you even confident that the app will display it's GUI panel on a real machine? prehaps you have a programmatic error such that the app itself never displays its GUI, regardless of how it's executed.