My brother has an iMac running Catalina. He purchased an Alesis Multimix 6 USB interface. He has both GarageBand and Logic Pro X. The problem he has is that he can record his guitar in GarageBand, but cannot record in LPX. The USB codec is recognized in the LPX preferences and selected as the proper input in the channel mix. No audio signal is visible in the meter and no audio recorded. This is the second interface he has purchased. Prior one was a M-Audio. Any help would be very much appreciated.