no waveform when recording

Hi there! I have been using Audacity for about 4 years with no issue. Same computer, same microphone. Recently, however, I have stopped being able to record. There is no waveform generated despite the microphone being plugged in and working well. Even when I use the microphone native to the computer, it doesn’t register any sound. I am able to import recordings without problems, just not record anything. I have checked the security preferences on my MAC and they allow the microphone to be used. I have viewed all the troubleshooting and forums and I’m totally lost! Any help would be so appreciated.

On Catalina you need to use this workaround: