[Zubersoft]

It's usually best to just get a USB-C to USB-B cable if that is what your keyboard expects as you can then avoid all adapters. Monoprice sells those for a couple of dollars, for example. Regardless, can you take a picture of Settings->MIDI Settings in MobileSheetsPro just so I can see what settings you currently have selected? As Rey_a mentioned, using the default MIDI library should probably work fine. We do need to figure out why you are not seeing any messages displayed if you bring up the MIDI listen dialog though. Also, as a side note, when you plug in a MIDI device to connect to MobileSheetsPro, the tablet will often ask if you want to load MobileSheetsPro by default when the device is connected.  It's usually best to decline that, as I've seen instances with some Samsung tablets where that would actually mess up the MIDI connection in MobileSheetsPro if the application was already loaded when you plug in the keyboard (as it will connect to the keyboard while the OS restarts the application unceremoniously due to the detected MIDI connection). You always want to accept the prompt that asks if MobileSheetsPro can communicate with the MIDI device though.

Mike