Possible cause: The credentials provided in the domain settings for that particular domain in ADManager Plus might not have sufficient permissions to access the deleted objects container in AD.
Click Domain/Tenant Settings.
Under Domain Configuration, all the domains that have been configured in ADManager Plus is listed.
Click the Edit Domain Details icon next to the desired domain where you want to add Domain Controllers.
Enter the credentials of an account with sufficient permissions in the Domain Username and Domain Password fields.
Note: Please check if the account has all the required permissions listed here.
Click Update.