I followed the K2 JavaScript Service Provider tutorials (https://community.nintex.com/t5/Technical-Issues/K2-JavaScript-Service-Provider-Preview/ta-p/125931) and was able to successfully upload a file to box.com. I've been reusing this working code to integrate with Adobe Sign but failing with NO_FILE_CONTENT error. The code snippet below seems to be the issue.
var form = new FormData();// get file nameform.append("File-Name", propertiesr"file1"].filename);// get file contentform.append("File", properties,"file1"].content);