I am trying to setup workflow so that when an object is created it sends an email to the person who created the object. As I can't seem to be able to do this out of the box (I have another thread Send email to creator of object when object created going)
I'm trying a workaround by having a field in the object that will capture the email and use that field to populate the Recipient field.

When I create the object and select myself in the User Picker custom field (Asset Owner) it successfully creates the variable and the email goes out as expected.
When I use select someone else OR someone else creates an object the automation is unsuccessful and throws an error (the object is created successfully though)
Note: The Actor in the Rule details is "Automation for Jira"
Any ideas why this error is occurring?