I'm using Nintex for O365 to create a simple workflow that posts to a Web Service using the Web Request action. I use string builder actions to build my JSON object in a variable, but when I use the variable in the body of my request I get an error returned stating "Request JSON object for insert cannot be null".
I've emailed the variable's value to myself and logged it to the history list, confirming that the variable has the correct value when I submit, and I can copy and paste the text into the request body and it works fine, just not when I actually use the variable as the request body. It almost seems like the variable is not encoded in a way the action can understand.
Has anyone else run across this problem? Thanks.