Why am I not receiving the Authentication SMS to my cell phone?

This is a known issue with Authy, If you use, or have ever used Authy for Two-Factor authentication for other sites or applications, you must use Authy to get your authentication token for Recurly. We would recommend downloading the Authy mobile or desktop application to move forward with receiving the authentication code. If you're unable to do this, you may want to have an admin user login and remove the 2FA requirement from your account. After you regain access, you can choose whether or not to re-enable the feature with a different phone number.