I am trying to import Subscribers into my Master Subscriber List using Automation Studio, upon running the automation I get an email sent stating the rows failed to insert and under reason it says the following:
ValidationErrors: Duplicate: 100
All of the records are definitely not in the Subscriber table either via the Subscriber Key or the Email Address (my subscriber keys are not the same as the email address).
Any ideas why this may be? I am working from the Parent Business Unit.