Hey there Nati,
These kinds of connection issues can be tricky to troubleshoot, so I'd be happy to help you figure this out. Would you be able to post a screenshot of the error so we know what the issue is? It would also tell us if it's a Google error or a Just Dance error, and we could troubleshoot appropriately.
I look forward to your response, and if you have any other questions or concerns for me, please let me know!