No Sound from Playback / Mixer and Synthesizer Disabled

I was working on a project earlier today and the playback was working just fine, but I opened MuseScore later during the day and all of a sudden the playback engine stopped working. The mixer and synthesizer options in the View tab were grayed out as well. I tried going through all the steps to get the sound back--reverting to factory settings, resetting I/O settings, and even updating to the latest version of MuseScore as of today (3.6.2), but I still don't have sound and the mixer/synthesizer are still disabled. Any other suggestions?