HTTP Code
400

Error Messages
Cannot delete active Account
or
Cannot delete Account with orders
or
Cannot delete Promotion with orders

Possible Cause and Solution
You attempt to delete resource, which can't be deleted because of some restrictions like existing connected resources, current resource state etc. Instead of deletion you may update Account and change it's status to cancelled. Notice, that it's not possible to delete Account or Promotion is it's connected with Order(s)