Garage Band not recognizing MIDI

I've seen this question answered before, and the solution was to reverse the MIDI cables. That's not my issue, though my symptoms are identical.

I’m not seeing any option for MIDI in sound input dialogue boxes in System preferences, as well as Garage Band (2011) preferences. I try using the keyboard in a GB window, but nothing is recorded within software instruments.

I’ve successfully used MIDI hundreds times, but it’s been several years. The piano keyboard is 17 years old. The Mac is using High Sierra. I’m trying two hardware interfaces, VicTsing (new) and MidiSport (old, with old driver—but it lights up and is detected). Both of these are recognized by my Audio Midi Setup. In both cases, when they’re plugged in, the computer alerts me that a new MIDI input is recognized. GB’s audio preferences says “2 MIDI inputs detected,” but immediately above that, in Audio Input, that choice is not listed. The VicTsing has two MIDI plugs; I’ve hooked them up in-with-out / out-with-in —and vice versa. The MidiSport has one plug-in, also tried in both outlets. I've learned that throwing new bits of hardware at it isn't the solution. Do you have one?