You only configure on DD side email address where you wish to send it.  If this does not arrive to you, check smtp log on smtp server to see if message has been received and delivered to inbox (that part obviously not) and what is causing it.  If email never reached smtp server, you will need to check mail log on DD (you can create support bundle I believe which should contain it).

really i configured the mail server in side of DD  and never have any mails from it

i configured the mail server as    SMTP.office365.com

i checked the EMC log can't reach anything related to mails

I'm pretty much sure that your smtp server is inside your organization just as your DD is.  Your inbox might be migrated to cloud, but I suspect smtp server is still within organization for stuff using DC on-premises infra (eg. Linux/UNIX/Windows boxes inside your DC might be using email alerts and they need to know about smtp server they must use too - and normally your AD is extended to cloud portion and this is all covered by your domain settings - if done that way).  You may ask around other DC teams in your area what do they use as smtp server.  Potential problem might be if your whole email business is outsourced to cloud and within premises you no longer have smtp infra or these components do not have trust between them - then you are kind of fried there, but I doubt someone would make such design without thinking about it.