This has no known fix from Microsoft but the following steps may provide some resolution to the issue, as reported on the Microsoft Community Support Page.

Please note that none of the below suggestions worked 100% of the time.

1. Log into Outlook on the Web (OOTW) and see if meeting still exists in the user's online calendar. If it does, the user will need to cancel the meeting on the web app and send a new request to all attendees.
2. Attempt to pull the meeting back from the deleted items folder. This can be done by searching for the meeting in the Deleted Items folder under the user's main email account in Outlook, on the left side of the screen. If the meeting is found, the user can attempt to drag and drop the meeting back over the Calendar icon on the bottom of the left side of screen. If this does work, the user can then go into the calendar and delete the meeting and send a cancellation through the desktop application.
3. Request an attendee resend the original meeting to the meeting owner as an ICS file. The owner should then attempt to import the ICS file into the calendar, then attempt to cancel it. If this works, user can then delete and send cancellation through the desktop application. 
4. Send an email requesting that attendees delete the meeting from their calendars, then create a new meeting.