If your device keeps restarting when MyVolumio is enabled, or you can't log in to MyVolumio on the device (for example after changing your password), a factory reset usually solves it.
If the device keeps restarting, disable MyVolumio first, so you can access the settings.
Go to
Settings→System→Factory Reset.After the reset, run the setup wizard and log in to MyVolumio again.
A factory reset restores all settings, so you'll need to set up your network drives and preferences again afterwards.