This is because the "Direct Printing" feature is not supported on IOS at this time.
Mobile Print Support.
On the new firmware 073.010.066.08210. We have try to scan the QR code to add a new printer in Xerox Print Portal v3.0.6. It doesn't Work with the display message : "printer a unavailable."
It's the only way to add a printer in this app. on IOS.
So we can't use Xerox Print Portal if we cannot add a new printer.
On Android device, we have the local tab in the "printer selection Menu". and we can add a new printer with his IP adress
the same phone and the QR code work with the Mobile Link.