Do you see the floating toolbar at the top of the screen? If not, do the following:
Right-click on the Vision icon in the taskbar of the teacher machine near the clock and go up to options > Show Shortcut bar.
Once you see the floating toolbar at the top of the screen, do the following:
Click the downward triangle section of the first icon to expand out a menu. In this menu select manage classrooms.
At this point either create a new classroom if there are none and check the ’make this my default classroom option’ or edit the existing classroom and check the default box on the first tab and click ok.
After creating or setting a default classroom, close the manage classroom screen and then click on the dropdown again and select the classroom you created or made default. Then click the button on the left of the dropdown menu and the class should open and stop this from occurring in the future.