A colleague has an issue where adding an extra attendee to an existing meeting in Outlook 365 sometimes yields an error.
Running Windows 10 x64, Outlook Click-to-run edition, connecting to an Exchange Online server.
The extra attendee is usually added in the Optional field. User then sometimes gets told (the following is translated, so wording might be slightly off):
"This meeting isn't on your primary calendar. Attendee responses won't be displayed in the meeting, but you can still receive responses in email. Do you want to send anyway?
However, this is his primary calendar, so the message is incorrect - and he needs responses to display in the meeting.
Please advise. Thanks in advance.