I have had this EXACT same issue ever since I upgraded to MacOS Catalina a month ago, and man am I regretting THAT decision. Add to that the fact that I can't update the software I paid $200 for because it mysteriously says it was purchased through another account...I really am getting sick of Apple and their $1000+ garbage machines. But rants aside, I tried using WAV, mp3, m4a, and AIFF file format without success. Even importing the audio file into Logic using the import function just results in an endless spinning of the Apple beach ball and me having to force quit the program. In fact, the ONLY workaround that worked for me was importing the file into a garageband project, then opening that project in Logic and copying and pasting the file over from that Logic project into the Logic project I was working in. Completely unecessary and totally unprofessional, and I'm thinking of switching to a different DAW just to get out of the clutches of Apple.