Please contact Instagram for assistance regaining access to your account.
If you had previously enabled Duo Mobile backup for third-party accounts on your phone then you may be able to restore that backup on your replacement phone to be able to generate passcodes for Instagram again.
Find more information about Duo Mobile backup and restore here: Duo Restore - Guide to Two-Factor Authentication · Duo Security
If you saved backup codes from Instagram when you enabled two-factor authentication you could also use one of those codes to regain access to your IG account.
If you did not previously back up Duo Mobile accounts then there is no way for Duo to restore your accounts, and Duo Support can’t help with Instagram logins. At that point your best bet is to contact Instagram for help.
What do I do if I’m locked out of Instagram, Facebook, or another third-party Duo Mobile account?
