I like to move an issue after creation automatically to a certain user via a workflow created in the workflow constructor. Prerequisite is "New issue created", action is "Update the value in a field". It issues the following error message, if I create an issue "Couldn't create issue. Cannot set value to custom field Assignee". What goes wrong here? Assignee is not a custom field. Even executing as admin with all rights granted does not make it work. What am I doing wrong? Thank you.