Apple - No devices are registered in the Developer's account
Problem sounds like you try to sign an adhoc app with your individual/company paid Apple Developer account. For this type of account adhoc distribution is for know devices (for example local test devices) only and need to known on which devices the signed app will be installed by signing.

From this devices the UDID will be crafted in the adhoc-profile. Your error message sounds like there are no devices linkend to your Xcode configuration so it can't create automatic a adhoc-profile that you need for singing and installation on a physical device.


  Xcode -> Window -> Devices and Simulators


There you can pair with physical devices, if that is already the case I would like to advice you to look at your generic identifier of your app because it needs to be unique to pass the system and get ready for signing.