If you're using the OTP from the email we send you, please start by deleting all OTP passwords from your email folder. Than sign in and wait for the next OTP email. It may take several minutes, please don't request another OTP email. When the OTP email arrives it will work.
If you've switched to 2FA (Two Factor Authentication). Remember that each number is good for only sixty seconds after it is generated. Also, make sure you're using the OTP code associated with CoinZoom.