Lightning to USB does not work

Since the last iOS Update of my old iPad Air to the latest available Version 12.5.7 I can not Connect my CME Xkey Midi-Keyboard via the apple usb Lightning interface anymore. The Keyboard is not recognized . Not Even the Message ‚device consums too much power‘ is displayed, which i have had with my usb-Audio interface. There I needed extra power. But extra power via an usb-hub does not work either. Any Idea, may Be the lightning connector is broken, or did anyone experience similar problems with this IOS-Version?