[otrs] Not getting the Email notifications!!!

Hi, I have a problem in getting the email notifications. When I create a ticket, there is no email notifications in my mail id. I checked out all the possible options related to email notifications. I can send mails to that id from some other web server(ex: from yahoo). But, only from otrs, I couldn't receive the email notifications. I checked: Admin Email, FQDN, user email, POP3 account, email addresses etc. Anybody, tell me What are all the possibilities for not getting the email notifications? Thanks, G.Anu.