# MQTT Source Connector error

**URL:** <https://forum.confluent.io/t/mqtt-source-connector-error/36481>\
**Category:** Self-Managed Connectors\
**Created:** [23 January 2025 15:16 UTC](https://forum.confluent.io/t/mqtt-source-connector-error/36481 "2025-01-23T15:16:40Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Metalmania97](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.confluent.io/metalmania97/32/4787_2.png) [@Metalmania97](https://forum.confluent.io/u/Metalmania97)\
**Post date:** [23 January 2025 15:16 UTC](https://forum.confluent.io/t/mqtt-source-connector-error/36481/1 "2025-01-23T15:16:40Z")

</div>

I try to set up an MQTT Source Connector with Kafka Connect running in Docker. I set the simple example used in the official Confluent page [https://docs.confluent.io/kafka-connectors/mqtt/current/mqtt-source-connector/overview.html#install-the-mqtt-connector-plugin](https://docs.confluent.io/kafka-connectors/mqtt/current/mqtt-source-connector/overview.html#install-the-mqtt-connector-plugin)  
without a license and i get this error in my docker logs  
ERROR WorkerConnector{id=MqttSourceConnector} Error while starting connector (org.apache.kafka.connect.runtime.WorkerConnector)  
java.lang.NoSuchMethodError: ‘org.apache.kafka.connect.util.TopicAdmin$NewTopicBuilder org.apache.kafka.connect.util.TopicAdmin$NewTopicBuilder.minInSyncReplicas(short)’  
at io.confluent.license.LicenseStore.setupAndCreateKafkaBasedLog(LicenseStore.java:185)

---

<div class="post-metadata">

**Author:** ![dtroiano](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.confluent.io/dtroiano/32/1961_2.png) [@dtroiano](https://forum.confluent.io/u/dtroiano)\
**Post date:** [23 January 2025 15:30 UTC](https://forum.confluent.io/t/mqtt-source-connector-error/36481/2 "2025-01-23T15:30:55Z")

</div>

This is a known issue that we are working to address. Specifically, it is a regression against Apache Kafka 3.8 (`apache/kafka` or `apache/kafka-native`) and Confluent Community 7.8 (`confluentinc/cp-kafka`). It would not crop up against Confluent Enterprise 7.8 (`confluentinc/cp-server`). For Apache Kafka or Confluent Community, I’d recommend downgrading to 3.7 or 7.7, respectively, to test this connector.