このエラーメッセージに関する原因と対処に関して説明します。
エラーメッセージ(英語)：
iot error the connection was lost
対処
関連リンク
AWS IoT Message BrokerのMQTTでpub/subをやってみた #reinvent ...
https://dev.classmethod.jp/cloud/aws/pub-sub-with-aws-iot-over-mqtt/
MQTT クライアントの ...
https://dev.classmethod.jp/cloud/aws/pub-sub-with-aws-iot-over-mqtt/#toc-mqtt-
AWS CLI のアップグレード
https://dev.classmethod.jp/cloud/aws/pub-sub-with-aws-iot-over-mqtt/#toc-aws-cli-
認証設定
https://dev.classmethod.jp/cloud/aws/pub-sub-with-aws-iot-over-mqtt/#toc-1
IAM Role の設定
https://dev.classmethod.jp/cloud/aws/pub-sub-with-aws-iot-over-mqtt/#toc-iam-role-
AWS Developer Forums: Testing publishing with mosquitto - ...
https://forums.aws.amazon.com/thread.jspa?threadID=218626
AWS Developer Forums: AWS IoT generated ...
https://forums.aws.amazon.com/thread.jspa?threadID=244897
AWS Developer Forums: Cannot connect MQTT ...
https://forums.aws.amazon.com/thread.jspa?threadID=228605
Diagnosing Connectivity Issues - AWS IoT - AWS Documentation
https://docs.aws.amazon.com/iot/latest/developerguide/diagnosing-connectivity-issues.html
【Raspberry Pi】AWS IoTとRaspberry PiでIoTをやってみよう ? kanenote
http://www.kanenote.org/blog/?p=986