Cognito Custom Message Trigger doesn't have any effect

Question

I am trying to customize the message sent to the user pre-verification by using the custom message trigger, I verified that the data returned from the lambda is valid and the modifications are as I want them to be, however it seems that those changes are not taking any effect as I get the standard verification details to my email

I failed to find any solutions in aws docs, anyone had the same issue ?

    package main

import (
    "fmt"

    "github.com/aws/aws-lambda-go/events"
    "github.com/aws/aws-lambda-go/lambda"
)

// Handler will handle our request comming from the API gateway
func Handler(event events.CognitoEventUserPoolsCustomMessage) (events.CognitoEventUserPoolsCustomMessage, error) {

    if event.TriggerSource == "CustomMessage_SignUp" {
        event.Response.EmailMessage = "Welcome to myapp, please click the following link to verify your email, this is a custom message"
        event.Response.EmailMessage = fmt.Sprintf(`Please click the link below to verify your email address. https://apigateway.myapp.com/auth/validate?client_id=%s&user_name=%s&confirmation_code=%s`, event.CallerContext.ClientID, event.UserName, event.Request.CodeParameter)
    }

    return event, nil
}

func main() {
    lambda.Start(Handler)
}

Answer 1

It seems that in the cognito panel under message customizations verification type code needs to be checked (not link), after I did that the trigger does change the message

Answer 2

It works also for verification link, but you have to use the code parameter as {##Verify email##} and not {####} in your User Pool - Message customization settings. And then also use {##Verify email##} keyword in your html template.