I have set 2FA on my gitlab account, and then deleted the google authenticator app on my phone. When I tried to login again, the recovery code that I've inserted didn't work, and so I downloaded the google authenticator app again, but the code in the authenticator app does not work when I try to sign in (I get "invalid two-factor code"). Changing my password didn't work :( Any help?
If your recovery code doesn't work, contact to Gitlab administrators. They will disable two-factor authentication for your account. For the future, you should better save QR code and keep it in a safe place. Then, if you lose your phone or delete Google Authenticator, you could easily restore it.