# MQTT Transmission Connection Lost Error

**URL:** <https://forum.inductiveautomation.com/t/mqtt-transmission-connection-lost-error/87354>\
**Category:** Maker\
**Created:** [March 14, 2024, 4:46pm UTC](https://forum.inductiveautomation.com/t/mqtt-transmission-connection-lost-error/87354 "2024-03-14T16:46:31Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![TChenier](https://avatars.discourse-cdn.com/v4/letter/t/d6d6ee/32.png) [@TChenier](https://forum.inductiveautomation.com/u/TChenier)\
**Post date:** [March 14, 2024, 5:36pm UTC](https://forum.inductiveautomation.com/t/mqtt-transmission-connection-lost-error/87354/3 "2024-03-14T17:36:59Z")

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Also, be aware the AWS IoT broker has a limit on message size. If Transmission publishes a birth with a large tag map that exceeds this limit, IoT Core will drop the connection.

> [@MQTT Transmission tag limit](https://forum.inductiveautomation.com/t/mqtt-transmission-tag-limit/82277/2):
>
> This is more likely due to AWS IoT Core's message size limitation of 128 KB. When a client publishes a message that exceeds the limit, IoT Core will drop the connection. [https://aws.amazon.com/iot-core/pricing/#:~:text=You%20can%20send%20and%20receive,metered%20in%205%20KB%20increments.](https://aws.amazon.com/iot-core/pricing/#:~:text=You%20can%20send%20and%20receive,metered%20in%205%20KB%20increments.)

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