The specified msg.topic is not supported

[Colin]

Since I have not got an S7 that flow does not help. Replace the S7 with an inject node to inject the data. Also see this canned reply for how to post flows here inline:

In order to make code readable and usable it is necessary to surround your code with three backticks (also known as a left quote or backquote ```)

``` 
   code goes here 
```

See this post for more details - How to share code or flow json