If you receive an 'Amazon Web Services Sign In: Your request included an invalid SAML response.' error message, that means that your NetID is not associated with any AWS account. See AWS - Granting Users Access to the AWS Management Console using NetID Authentication for setup instructions.
Creating an AWS Account Alias
To make it easier to identify an AWS account after NetID login, you can create an AWS Account Alias using the documentation at Your AWS Account ID and Its Alias.
Amazon IAM user login
To sign in to the AWS Management Console using an Amazon IAM user, open the IAM users sign-in page associated with your account. This URL is formatted https://<AWS-account-id>.signin.aws.amazon.com/console where <AWS-account-id> is your 12-digit AWS Account Id. It is recommended that all AWS accounts have at least one IAM user with AdministratorAccess permissions that can be used without requiring NetID authentication, this account should be secured with MFA to comply with UW System authentication standards.