Start Workflow via JS gives error "Value cannot be null"

Question

Hi I am attempting to start an SP 2010 workflow using Jquery SP Services but i seem to be getting a response 500 Value cannot be null. There is not supposed to be an initiation form yet when i manually start the workflow via link i get an infopath form with just Start Cancel buttons as i have no parameters. Can anyone spot an issue?

 $().SPServices({
            operation: "StartWorkflow",
            item: "https://mytenant.sharepoint.com" + fileRef,
            templateId: "{463231b0-e608-44e1-ae9f-57af1832565d}",
            workflowParameters: "<root><data></data></root>"
        });

Answer 1

Based on the first example on the StartWorkflow documentation, it looks like your workflowParameters should be "<root />".

I think by having <Data></Data> in there it is expecting that there be a parameter in there and is erroring out when there's nothing in there.

500 errors are Server level errors, so it may be valuable to log the item url to make sure the fileRef variable is pulling in a correct URL also.