There could be a few reasons why you're having trouble logging into your Amazon A to Z account. First, make sure that you're using the correct email address and password. If you've forgotten your password, you can reset it by following the link on the Amazon A to Z login page.
If you're still having trouble logging in, it's possible that your account has been deactivated. This can happen if you haven't used your Amazon A to Z account in a while, or if Amazon suspects that your account has been compromised. If your account has been deactivated, you'll need to contact Amazon customer service to reactivate it.
You can find the Amazon A to Z customer service contact information here: https://www.amazon.com/gp/help/customer/contact-us?ie=UTF8&nodeId=508088&ref_=ya_contact_us