That's by design. To ensure lowest latency playback of audio, SFX uses the ASIO driver model and opens/locks the sound card when a show is opened. The work around is to install a 2nd sound card. There are some USB sound devices out there that are very affordable that would work fine as a 2nd device so you can meet with your students and also run SFX.
Thanks much! I assumed that it was a safety feature of some kind, I figured it kept the facebook alert ding from interrupting your production of "A Dolls House". Is this https://www.amazon.com/UGREEN-External-Headphone-Microphone-Desktops/dp/B01N905VOY/ref=sr_1_1_sspa?dchild=1&keywords=external+sound+card&qid=1598620266&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExM0xORDBJTUhYNDlIJmVuY3J5cHRlZElkPUEwODc5NTkyMVpHOE9PNk1QMkNKMiZlbmNyeXB0ZWRBZElkPUEwMDQzNjk5MkFXWFlQUExXVTFQOCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU= the type of thing you're referencing? I'm a misplaced scenic designer tossed into a sound world, so I appreciate how helpful you and the rest of the forum has been.