error 400 signup on amazon / cognito

[Gareth Murfin]

Im trying to sign up on cogniti on amazon like this https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_SignUp.html

I think im submitting everything right, plus headers and content type but I get a reponse Unhandled error code: 400 for https://cognito-idp.eu-west-1.amazonaws.com

is there a way to get a better error message? I tried r.setReadResponseForErrors(true) with no difference. it looks like there is a list of better errors they throw like CodeDeliveryFailureException etc, but how do i get which one it is?

[Shai Almog]

Look in  the Network Monitor and see the response. It usually includes the full error even for error code responses.