Unfortunately, no one can help you here. You should contact their support.

I remember that cryptopia encouraged all users to use Google Authenticator/Authy or Cryptopia Authenticator as they say it's the highest level of security. They provided a security warning to those who are using low level of security which includes 2FA email and 2FA pincode. I have been using email auth before and that notification popped up as well in my cryptopia account, that's when I decided to change my 2FA settings.

Aside from that, there have been several issues of not receiving email codes too. Maybe another reason for them to discourage users of using it.