How to restore the "2FA" survice

[Zhihong Zhang]

I've accidentally deleted the "u-tokyo email account" in "Google Authenticator", and I forget the key related to my u-tokyo email account, so I cannot provide the 6-digit code via "Google Authenticator" when I want to sign in the u-tokyo email "https://mail.iis.u-tokyo.ac.jp/". I request to restore the "2FA" survice so that I can restart to using the "Google Authenticator" to configure the "2FA" survice.
Thankyou so much for all your potential possbile adivices.