[AWS Greengrass] Core device fails to connect to AWS IoT Core over Charles proxy.

I am trying to connect my Core device (Raspberry Pi 3 Model B) over Charles Proxy.

1. I set up the Charles proxy on my laptop.
2. I updated the Nucleus configuration by deployment.

{
  "networkProxy": {
    "proxy": {
      "url": "http://192.168.0.38:8888"
    }
  }

3. Added the Charles Root Certificate to the core device's Amazon root CA certificate file as it is described in Enable the core device to trust an HTTPS proxy.

Actual result: The device cannot connect to AWS IoT Core.

2023-04-04T12:44:19.588Z [INFO] (pool-2-thread-12) com.aws.greengrass.mqttclient.AwsIotMqttClient: Connecting to AWS IoT Core. {clientId=rpi_3_B}
2023-04-04T12:44:22.102Z [ERROR] (Thread-4) com.aws.greengrass.mqttclient.AwsIotMqttClient: Unable to connect to AWS IoT Core. {clientId=rpi_3_B}
software.amazon.awssdk.crt.mqtt.MqttException: socket is closed.
        at software.amazon.awssdk.crt.mqtt.MqttClientConnection.onConnectionComplete(MqttClientConnection.java:140)

2023-04-04T12:44:22.110Z [ERROR] (pool-2-thread-12) com.aws.greengrass.mqttclient.MqttClient: Error when publishing from spooler. {}
java.util.concurrent.ExecutionException: software.amazon.awssdk.crt.mqtt.MqttException: socket is closed.
        at java.base/java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:395)
        at java.base/java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1999)
        at com.aws.greengrass.mqttclient.MqttClient.runSpooler(MqttClient.java:659)
        at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
        at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at java.base/java.lang.Thread.run(Thread.java:829)
Caused by: software.amazon.awssdk.crt.mqtt.MqttException: socket is closed.
        at software.amazon.awssdk.crt.mqtt.MqttClientConnection.onConnectionComplete(MqttClientConnection.java:140)

Unfortunately, I cannot attach .csv or .chls files.

Any idea why AWS IoT Core is terminating the connection?