Microsoft Outlook not syncing with Server! HELP PLEASE

Hi guys,

My email (used to be hotmail, now become some outlook web app thing) (let's call this A) is synced to my microsoft outlook (let's call this B).

In the past, whenever I delete my email in A or B, the other side will be updated automatically.

However now, when I delete a mail in A, B will be updated. But when I delete a mail in B, A will NOT be updated. Any ways to make the "server" (A) be updated automatically whenever I delete the mail in B?

I will really REALLY appreciate any help / advice. Thanks!!!