Could not send an email

Could not send an email

Dear Team,
                    This is regret to tell you that, I am currently facing the problem to send a simple email. I dont know what is the wrong with my account. When I am trying to send an email I get this message: " Unable to send message;Reason:554 5.1.8 Email Outgoing Blocked".
                   Please do the needful regarding this as soon as possible as it is my newly created official email -id.

Regards,
Sayan Ganguli