Reset root password of AWS account

Hi,

we are trying to reset the password of an internal AWS account (AWSAccountID: ***************).

These are the instructions we have received:

• Make sure the email address for this account accepts external mail. a. If the email is a majordomo list, set it here https://mail-admin.amazon.com/cgi-bin/email-list.cgi b. If your email is an exchange-list, cut a ticket to IT Support > Email - Exchange - Outlook - Calendaring> Email List Tool (email-list.amazon.com)
• Reset your password at https://signin.aws.amazon.com/signin?redirect_uri=....

When I try to follow the 2nd step, the following error appears:

 Password recovery failed
Password recovery is disabled for your AWS account root user. You need to re-enable this feature. If you're not an internal Amazon user, contact AWS Support. 

Can you help me to reset the password of this account?

Best regards,

Víctor Rodrigo.