When accessing the Authy app, some users may see the following error message:
Multi-device is disabled for your Authy account, so you cannot currently add new devices. You can change this setting in the Settings section of the Authy app on any other device. If you do not have any active devices, visit authy.com/phones/reset to recover your account (this process takes up to 2 business days).
This guide covers the most common ways to resolve this error.
Enable (or disable) Authy Multi-Device
Authy Multi-Device can be used to allow multiple trusted devices to use the same Authy account and 2FA tokens. This can be a good option for users with a number of devices like a mobile phone and a tablet, or a desktop computer and a laptop. We encourage all Authy users to configure another app installation to use as a backup. Once your backup device is enabled, you can disable Multi-device to prevent the risk of any unauthorized devices being added (This will still allow you to access your account from all existing devices).
For full details, see Enable or Disable Authy Multi-Device.
With Multi-device enabled, you can download and install the Authy app on multiple devices, and sync your 2FA tokens between them. To setup another Authy app installation on your account, just download the app on your desired phone or computer, and then then login with your existing account information. See Installing Authy Apps for download links.
Perform a device recovery
If Multi-device is not enabled, and you don't have access to another trusted device on this Authy account, you then you would need to recover your account.
Notice: Account recovery will completely wipe any existing configured Two-Factor Authentication (2FA) accounts, and will take 24 hours (This cannot be expedited, since this is a security measure to protect your account).