I'm asking this question because I was surprised how little information I could find from Googling. However, I was able to track down what I think is the root cause. I'll share it as an answer and see if someone is able to elaborate or provide a better explanation.
So, to clarify, I'm using the AWS JavaScript SDK for Cognito. When I tried some of the standard use cases, I received the following error:
Client is configured for secret but secret was not received
What steps can I take to resolve this?
