Errorcode 80071392 when creating User

Errorcode 80071392 when creating User

Hi there,

when trying to create a new User via my own Usertemplate in aDManager Plus I receive the Errorcode  80071392: The Object already exists.

Unfortunately I created rules, so when ADManager detects a duplicate Username it just adds a Number to it. But I think it isn't working...

Then I tried to add the Number manually by myself. But the erorr still exists. I am on the newest Version of ADManager Plus. 
What could be my mistake?

Thank you!

                New to ADSelfService Plus?