It sounds like you’re running into a connection issue with the PhoneBurner Sync app. Since you're using the free version, it’s possible that some features might be restricted.
Here are a few things to try:
Double-check your login credentials and make sure your account is active.
Ensure that you’re using the correct app ID and that it matches what’s in your PhoneBurner account.
Try restarting the app or reinstalling it.
If it still doesn’t work, you might want to reach out to PhoneBurner support—there might be an issue on their end.