Cognito didn't error on missing required email

Hi,

From the description of your issue it appears that you are using standard attributes for your Amazon Cognito. Standard attributes are optional by default for all users. To make an attribute required, during the user pool creation process, select the Required check box next to the attribute. From the documentation here[1] I can confirm that “When you mark a standard attribute as Required, a user can't register unless they provide a value for the attribute”.

Reference: [1]. AWS Amazon Cognito User pool attributes documentation: https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-settings-attributes.html

Thank you.