Error with Emulator on the MIT App Inventor website

I work in a school and we have been trying to use the App inventor with the students. They create the phone and everything and when we try to connect the phone via the Emulator it will either say that there was a connection problem or it will connect but then we get nothing to display. Has anyone else had the same problem and if so how did you fix the problem.

Thank you

Basta disconnettere la connessione e riconnettersi ad internert..oppure chiudere e riavviare il companion.

Welcome Lily.

Have you ever been able to connect or are you just starting to use App Inventor? I know you want to build using the emulator but can you build using a real device and the Companion? Knowing that might help us isolate your issue.

After you installed the emulator, did you load a Project after you started the emulator (Connect > Emulator)?

There are many possible reasons you are having issues. At the moment, I can only guess. The problem could be issues with your school network or attempting to load large Projects or a very slow School network. The information in the following links might help you to resolve your issue (especially the first and the second link).