I am attaching a file from a form as part of an approval request flow. Once done, I am receiving an error "The response is not in a JSON format."
What is going on? What can I do to correct it?

I am attaching a file from a form as part of an approval request flow. Once done, I am receiving an error "The response is not in a JSON format."
What is going on? What can I do to correct it?