Exam AWS Certified Developer - Associate DVA-C02 topic 1 question 230 discussion

To allow an ALB to invoke a Lambda function, you need to grant the ALB permission to invoke the Lambda. This is typically done by adding a resource-based policy to the Lambda function, granting invoke permission to the ALB. If this permission is not set, the ALB will not be able to trigger the Lambda function in response to incoming requests.

https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html Permissions to invoke the Lambda function If you create the target group and register the Lambda function using the AWS Management Console, the console adds the required permissions to your Lambda function policy on your behalf. Otherwise, after you create the target group and register the function using the AWS CLI, you must use the add-permission command to grant Elastic Load Balancing permission to invoke your Lambda function. We recommend that you use the aws:SourceAccount and aws:SourceArn condition keys to restrict function invocation to the specified target group. aws lambda add-permission \ --function-name lambda-function-arn-with-alias-name \ --statement-id elb1 \ --principal elasticloadbalancing.amazonaws.com \ ....

C is the correct answer.

The Lambda function must have the lambda:InvokeFunction permission for the ALB to successfully invoke it.

ANS: C

C. The permissions to invoke the Lambda function are missing.