Have you tried to uninstall and reinstall the mobile application? I know it sounds silly, but sometimes an update doesn't go through properly and it can cause issues like that because it doesn't properly link to the login server.
If you want to setup a new account and new email, you can do so, but you'll need to complete a factory reset (I'll link the process below) and then, when logged into the new account, set up the unit again like it's brand new.
I hope this helps!!