We recently changed our name servers to point to Office 365 from an old hosted exchange server (over 72 hours ago).
We are noticing though that some mail is still being delivered to the old boxes...
We updated the name servers at our registar to point to the office 365 servers, and most new mail is arriving on the 365 server, but there still seems to be something strange.
Could it be propagation still??
If people on the internet respond to older messages from us (generated from the old server) will they route back to the old server? Could this be the issue?