We have been moving some customers over to Office 365.

Here are some of the steps required to do this.

1. Setup the account in Office 365.
2. Use the migration tool
3. In Office 365 go under Setup >> Domains >> give it a second and it should populate the 3 records you will need to update.
   MX
   TXT
   CNAME
   
4. We removed all the older record pertaining to SecureServer.net which was POP, SMTP, CNAME, TXT, and the MX record.
5. Added the 3 records shown above.
6. Sent a test and received the email. Replied back and was able to verify the customer could receive the email.

Let us know if this helped you…