AWS SES Email verification through our app

Hello! We have an app that monitors solar panels on behalf of our customers. We are using AWS SES to email and notify from within the app. We send a verification email when we add contact info. The email from Amazon looks very suspect and many customers think it's spam. I want to customize this verification email with our message and branding so people know it's from us. We have requested this from AWS and and gotten denied multiple times for "security reasons" they can't share. I find this baffling! It seems like such a basic request. Any guidance?