When you use the 2FA security via Google Auth, it becomes locked to that device via QR code. On the page where you sync with the QR code, there will be another code, please remember to write it down, in case you ever need to set up your Google Authenticator again.
If you disabled Google 2FA and are trying to resync use a new device, you can use the code that you were given when first synced.
You can also request for your sync data to be reset, if you do not have the number.
Note: Due to security issues, there will be a minimal of (1) one week waiting period to make sure your email address has not been compromised.