The screen alone may not be the difficult part. A meeting brings voices, a different way you speak and a period when you stop responding to your dog. You cannot infer the trigger without watching the first moment they change. For now, let them leave the room and rest somewhere they will not be disturbed.
Do not insist they sit beside a loud speaker or repeatedly start a call to test them. Set the volume low enough for comfort and give them access to their usual water and rest space. If the reaction is sudden, severe or spreads to ordinary sounds, speak with your vet. The article on making a quiet space helps with a retreat they can choose, not a place to lock a frightened dog away.
Outside an important call, compare what happens when the laptop is open silently, when a familiar person speaks at a low volume, and when you speak in your meeting voice. Change one safe cue at a time and stop if the dog hides. A qualified reward-based professional can help if practice is hard to keep gentle. Dogs Trust and VCA both advise keeping sound work below the level that makes the dog afraid.
Today, give your dog a choice of room before the next meeting and note the first cue they react to. They do not need to attend your call.
Sources: Dogs Trust on noise fear and safe retreat, VCA on noise-fear assessment, VCA on gentle desensitization.