In essence what I want to do is look up a user's Account Name from the SharePoint User Profile Service by inputting another unique field. In this case it is a custom Employee ID field in the UPS that is read from AD, but it could be by phone number, or other fields.
To clarify, I am inputting an Employee ID number and wanting to extract the username that matches up with the Employee ID.
I've tried setting a variable as shown in the attached file, but that errors out with "Workflow failed to get user profile for user".
I have confirmed that the property is readable from the User Profile service in Nintex, by using a Query User Profile action, hard-coding a user in and emailing the Employee ID number.
Thanks for any advice!