ISSUEWhen running a workflow, it fails on the "Set Item Permissions" action and the following error is logged on the workflow history page:
An error has occurred in "workflow name".
Additionally, the SharePoint ULS logs contain the corresponding error related to the above error.
Nintex.Workflow.NWException: Failed to set permissions (-2130575276). ---> Microsoft.SharePoint.SPException: The user does not exist or is not unique