Q: syncing calendars...

I am adding "Grab" partial screen shots but they dont show up like urs do.

That's okay.  Tell me if all of your calendars are listed under the iCloud heading, even though the are empty.

Then, let's back up your calendars to your desktop.  Begin by checking only the calendars that actually contain your events (and uncheck any others, such as the ones listed under iCloud).  Then click on each of the calendars that contain your events one at a time and go to File>Export>Export and save each of these on your desktop.

Let me know when you're done creating these backups.

I backed up the only important calendar to my desktop.  The others called work adn family  I am ignoring adn hope they go away.

Now go to System Preferences>iCloud, uncheck Calendars & Reminders, and choose Delete from My Mac when prompted.  Then restart your Mac.  After it restarts, to to System Preferences>iCloud, check Calendars & Reminders and when prompted about merging with iCloud, choose Merge.  There will be a delay as your calendars are uploaded to iCloud.

When it's done merging with iCloud, uncheck all the calendars except the ones listed under iCloud (there may not be any other caledars except the ones listed under iCloud at this point).  Then see if your events appear on your calendar.  If they do, check icloud.com and see if they appear there as well.  If they do, check the calendar on your phone and see if they appear on your phone.  Let me know what your results are.

the phone adn mac appear to be synced.  Howver google is "upset."  I keep on getting this diagnostic

https://www.google.com/calendar/dav/svrobrien@gmail.com/user///www.google.com/calendar/dav/svrobrien@gmail.com/user/ is not a location that supports this request.

It continues to appear every time I open the calendar on the mac.  Thanks for all your help.  Any adivce you have about dealing with this google msg would be most appreciated.

Please post your question separately as it does not relate to this discussion.

Thanks again for all your help.  The problem went away when I unclicked adn reclicked Cal adn REminders in the mail, contacts & calendars area of Mac settings.

You're welcome.  Glad it's working again.  The calendar backups were only a precaution, but it's always a good idea to back them up from time to time like this in case something goes wrong with your iCloud clandar.

Also, if there are calendars you no longer want you can control-click on them and click Delete.  Be sure you no longer want them if you do this as it is permanent.