Calendar not uploading to iCloud

I recently acquired a 2019 MacBook Pro to replace my older model. I restored it using Time Machine and upgraded to macOS Monterey. Everything seems to work fine, except the Calendar app. Contacts and Notes upload to iCloud as they should, but Calendar will not. e.g., if I add something to Contacts or Notes, it shows-up on my other devices. If I add an event to Calendar it does not show-up on my other devices. Also, when I look at my calendar at iCloud.com the event is not there. So the problem appears to be that Calendar on my MacBook Pro is not syncing with iCloud.

Time and date are the same on all my devices and are set automatically, so that does not appear to be the problem. I've tried disabling and re-enabling my account in Calendar preferences (which are set to "Push") and unchecking and rechecking Calendar in the System Preferences under Apple ID. None of these help.

Any suggestions on how to get Calendar to sync with iCloud would be welcome.