This means that the RCM invites were not found in the Calendar Migration Tool’s detection process. This could result from the RCM invites being changed. To fix the error, try running the migration tool again.
Keep in mind that the Calendar Migration Tool may not update customized meeting invites. For example, if a user has made changes to the meeting details information that populates when you schedule a RingCentral Meetings session, such as the meeting invite URL or dial-in information, the Calendar Migration Tool will be unable to update this invite to a RCV meeting.