workflow.asmx giving error after starting workflow process

Copper Contributor

/<site>/_vti_bin/Workflow.asmx is called to start workflow for an item and it finishes as "Cancelled" and error "Coercion Failed: Input cannot be null for this coercion"

5 Replies



Please share more details about your issue. Are you using any initiation variables in your workflow if yes then you need to pass it while starting workflow using web service, Could you share input which you are providing to web service method?


Right now, I'm testing using Postman and method is POST


            <root />
The workflow starts but terminates as "Cancelled" with that error "Coercion Failed: Input cannot be null for this coercion."



Do you have any initiation variable in the workflow? if yes then could you share those details with type of variable? because we need to past those value as well.




Also share which SharePoint version your are using? and which service method you are using from workflow.asmx service endpoint


I'm using "Custom List - Workflow Settings"

Method is "StartWorkflow"


Does anyone have an idea?