Invalid Lambda Response says Text can't be empty or null. How to fix?

Question

I've programmed a lambda function to return an ElicitIntent with a "contentType" of "application/vnd.amazonaws.card.generic". When Lex receives the response it throws this error:

```
An error has occurred: Invalid Lambda Response: Received invalid response from Lambda: Can not construct instance of Button$Builder, problem: Text can't be empty or null
```

I don't understand "Text", with the capital T. There is no "Text" in my return response. I have "text" as part of my buttons but they are not empty.  
I'm confused. Any help appreciated.

Answer

Thank you for using Amazon Lex.  
Please check if the length of the button text is between 1 to 15 characters. Let us know if you're still seeing issues.  
  
Reference : https://docs.aws.amazon.com/lex/latest/dg/API_runtime_Button.html

Answer

So it turns out it's the LENGTH of my text. The text can't exceed 15 characters.

Invalid Lambda Response says Text can't be empty or null. How to fix?

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