Hi @freds, welcome to the forum.
Firstly,
Your flow is not importable. it is important to surround your code with three backticks
```
like this
```
You can edit and correct your post by clicking the pencil icon.
See this post for more details - How to share code or flow json
Question. Do you have multiple MQTT configuration nodes with the same client ID set? Client ID must be unique or the broker will cause disconnects.