If you have already [changed your password] but still cannot log in, you can try updating the Sync APP to the latest version to solve the problem.
Please make sure your computer's operating system meets the minimum requirements：
Windows 10 (or higher) / OSX 10.13 (or higher).
Uninstall/Reinstall Sync APP
1. In the Windows search box, type "control" and select it from the results.
2. Then select [Programs] > [Programs and Features].
3. Right-click on the Sync APP and select Uninstall or Uninstall/Change. Then follow the directions on the screen.
4. Restart your computer.
6. Try to log in again.
7. If you have tried the steps above, but the problem persists, please fill out a problem report form.
1. On the left menu of Finder, click [Applications].
2. In the [Application], find the Sync APP, and drag it to the trash can.
3. Restart your computer.
5. Try to log in again.
6. If you have tried the steps above, but the problem persists, please fill out a problem report form.