Outlook not receiving emails

My daughter's outlook account is not working properly.  I can send her an email from my ipad, but if I go onto the web and send from my msn email it bounces back....she has friends who have tried to email her and they have also bounced back. She can send emails.  She has not changed any settings or upgraded.  I have looked at her email settings and all seem normal....no blocked senders, no filters etc.....we are considering setting up a new account for her :( you are our last hope :) thanks xx