I don't think so. I have been syncing with the outlook.office365.com server for months now, ever since we migrated over to Office 365. It's worked just fine. I was also able to set up a POP account with that server.Is there any chance your corporate email accounts were upgraded from the older Office 365 servers to the newer servers?
Talking with brick walls is usually more gratifying than asking my IT for support. Perhaps I will open a ticket here just for the fun of it.If you want IMAP support I encourage you to have your IT support open a ticket too and ask if IMAP is still supported?