Google calendar error on startup

I’m a new user. Why do I keep getting an error message about my Google calendar: “Uploading item(s) to folder ‘Gmail/…@gmail.com/’ failed with an error: The owner of the calendar must either be the organizer or an attendee of an event that is imported”?

My calendar updates fine, but I keep getting this message.

Hi,
what version are you using? You can find the exact version number in Help > About. Also could you go to Tools > Settings > Advanced and turn on GData logging under your Gmail account? Save the settings and restart the application.

When the error shows up again, please go back to the Advanced settings window and click on Send Logs, please add my email to copy mcgregor@emclient.com.

Thank you, and sorry for the belated reply,
Paul.