For optimum security, every account is recommended to utilize 2 Factor Authentication.
If you are having problems while using U2F, please check that the browser you are using is compatible with Ethfinex. This can be viewed on our Supported Browsers & Platforms page.
If needed, Ethfinex can also reset 2 Factor Authentication on your account. But prior to disabling your old U2F, we would need to establish beyond doubt that you are the legitimate account owner.
To do this, contact Ethfinex by submitting a ticket on our support page mentioning that you have lost your U2F 2FA. You will then receive instructions on how you can provide proof of your identity.