AWS SQS messages stuck in flight when using Lambda triggers

Question

I have configured a queue with a DLQ with maximum receives value to 5. The lambda was configured to pool 1000 messages in a 30 seconds batch window. Whenever the lambda processor receives an invalid messages, it will throw an error and I assumed the messages will eventually moved to DLQ when it reaches the receive count >= 5. But the messages are stuck in flight. And it seems the lambda processor wont retry those messages. Should I update the visibility timeout or any message attributes in the lambda processor just to make those messages visible again, retried and eventually moved to the DLQ?

Answer 1

If the SQS Queue is KMS encrypted. Make sure that the Lambda IAM role has permissions to decrypt the KMS key.