I have performed a staged migration up to this point migrating our inboxes to office 365. I have most all the accounts on office 365 but their are 2 email addresses that I haven't been able to move because they are tied to a printer and our website and they don't play nice with the smtp.office365.com/587 address. Even with SSL enabled and using an account login credentials I am still unable to get them to send through office 365.
So my question revolves around the final steps. I am wondering if I change my MX record to point to office 365 rather then our internal exchange server will these email inboxes that I am unable to move continue to work through the exchange server? I have no plans to decommission the exchange server because I still need the utilities to be able to administer office 365. I just need to know if these accounts will...