# org.apache.kafka.common.errors.DeadLetterQueueException: Failed to send record to dead letter topic DLQ_topic

- **ID:** `kafka/dead-letter-queue-producer-exception-on-send`
- **Domain:** kafka
- **Category:** runtime_error
- **Verification:** ai_generated
- **Fix Rate:** 76%

## Root Cause

A Kafka Streams or Kafka Connect dead letter queue producer encountered an error when attempting to forward a failed record to the configured DLQ topic, often due to serialization or ACL issues.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| Kafka 3.4.0 | active | — | — |
| Kafka 3.6.0 | active | — | — |
| Kafka 3.7.0 | active | — | — |

## Workarounds

1. **Verify the DLQ topic exists and has correct ACLs using 'bin/kafka-topics.sh --bootstrap-server localhost:9092 --describe --topic DLQ_topic' and 'bin/kafka-acls.sh --bootstrap-server localhost:9092 --list --topic DLQ_topic'.** (88% success)
   ```
   Verify the DLQ topic exists and has correct ACLs using 'bin/kafka-topics.sh --bootstrap-server localhost:9092 --describe --topic DLQ_topic' and 'bin/kafka-acls.sh --bootstrap-server localhost:9092 --list --topic DLQ_topic'.
   ```
2. **Ensure the DLQ producer uses the same key/value serializers as the main topic. In Kafka Streams, set 'dlq.topic.name' and configure 'default.key.serde' and 'default.value.serde' correctly.** (82% success)
   ```
   Ensure the DLQ producer uses the same key/value serializers as the main topic. In Kafka Streams, set 'dlq.topic.name' and configure 'default.key.serde' and 'default.value.serde' correctly.
   ```

## Dead Ends

- **Setting producer retries to Integer.MAX_VALUE** — Increasing producer retries only delays the eventual failure; the root cause is usually misconfiguration. (85% fail)
- **Removing the DLQ configuration from the connector** — Disabling the DLQ entirely loses the failed records and defeats the purpose of error handling. (95% fail)