Here are troubleshooting steps to resolve a shared screen issue on your mobile device:

1. Make sure you joined the meeting as a participant (not a presenter).
2. Check if Android 7.0 or earlier is installed.
3. Try restarting the Teams app.
4. Quit the app completely and launch again.
5. Check if you have the latest version of Teams.
6. Try switching your device to Airplane Mode and back before restarting the Teams app.
7. Ensure that your device connection is stable.
8. Try connecting to a different Wi-Fi or cellular data network.