If students say that that they see a green screen while you're sharing screen, similar to the below image, then please follow the below steps.

Step 1: Open Teams and click on the 3 dots in the top right corner and click on settings.

Step 2:  Tick the box labelled Disable GPU hardware acceleration (requires restarting Teams).

Step 3: Close the box, click back onto your initials and select sign out.

Step 4: Open Teams and sign in.