ISSUEWhen running a Workflow with Call Web Service action to start another workflow, this error might occurs:
Error The selected workflow <workflow name> is already running on list item with ID <Item ID> in list <list name> on site <site name>
RESOLUTIONAdd Pause action before the Call Web Service workflow.
ADDITIONAL INFORMATIONThe root cause of the issue is because the same workflow required to be called several times in the short period time. Adding Pause action is to make sure the previous workflow instance has been completed before another workflow being triggered.