get root login to my iAM user

If you can login to one of the accounts, change the email associated with that user account. You should then be able to log into the other account and update your card.

Hi there, two AWS account cannot have the same email address. However, if you are receiving emails from two different AWS accounts then likely what happened is that you might have opened your original account (5678) with your actual email address and the second one by appending a "+" and another string, i.e. "+1234@..". If the mail server supports it, it will forward the email to the original email. If you are trying to figure out the root email for account "1234" then I'd recommend looking at the "to" field of the emails you're receiving for both account as you will see the email address used to open the account. Once you have it you can then go through the normal reset password workflow for the root user.