Cannot get rid of audio error message

I use Zoom most often for webinars that do not require me to actively participate in the meeting and so I keep my computer's security setting allowing access to my microphone switched off most of the time. However, since the last update, whenever I log into a meeting, I get a pop-up alert that Zoom failed to detect my microphone, and there is a little red exclamation point error over the Audio icon in the bottom left of the screen for the length of the meeting. (Note that my computer security setting allowing access to my webcam is also off, yet I don't get any error message for my video, and it shows the normal crossed out video camera during the meeting rather than an error message.) Is there any way I can fix my settings so that I don't get that that error message for my audio?