If you lose your mobile device or don't have access to your device, and don't have access to the recovery codes you had downloaded when you were enabling two-factor authentication, here is how you can regain access to your accounts. 

In the 2FA screen where you are asked to enter your authentication code, click on 'Unable to access your authentication code?"

You will be redirected to the screen where you can enter the recovery code instead to gain access to your accounts.  

If you don't have access to the recovery codes, you can click on the 'Request recovery code from the organization admin' link seen on the screen. Once the request is sent to the organization admin, you will receive the one-time recovery code via email.