unable to remove seconary mail

unable to remove seconary mail

I am trying to delete the secondary email address manjeet@kkmengg . com  .
When I click delete, I receive the following message -- " Please contact your Organization administrator ravi@kkmengg.com,to delete your email address."  I am logged in as administrator ravi@kkmengg.com
so I don't understand why I can't delete it? and all mails are forwarding through manjeet@kkmengg.com but i want them as ravi@kkmengg.com

please remove the secondary mail   manjeet@kkmengg.com  as i want it to be a user not  an admin.

searched the forum and this is a task many user have faced earlier and only support have able to resolve it from backend please make the needful changes also dropped the mail at support@zoho.com but didnt receive any response yet.