Outlook meetings not showing up on other user's calendar

We are using Office 365, and when Jane (Windows 7), who has full access to John's Calendar creates a meeting invite, it shows up in his Outlook on his Mac, but does not show up on either calendar Jane has (shared or team).  A test meeting invite later in the day resulted in the meeting showing up on Jane's team calendar for John, but on John's machine, did not appear at all.  Up until today, there were no issues or problems with the creation of meetings and both users being able to see the meetings as scheduled.

Any suggestions as to what may be the problem and how to fix it?  Thanks.