Lost data from emclient. Error: Uploading item to folder...Request parameter validation failed for [Google.Apis/Requests/ request.....

I have lost data from emclient. How do I get my calendar entries back? My version is: 7.2.34062.0. A few weeks ago, it stopped synching to gmail calendar. A few days ago, I clicked refresh and got an error message. It just didn’t synch but the info was still there. Today, when I clicked refresh I got a new error message and the data disappeared. There is now more on my gmail calendar (although it also wasn’t fully updated due to the earlier failure to synch). How do I get my calendar entries back? I am copying error message here: "Uploading item to folder…failed due to the following error. Request parameter validation failed for [Google.Apis/Requests/ request…

Is anyone able to address this problem?  I have changed the Google settings to enable less secure apps.  Should I close the app and see if my calendar entries return?  Where did they go?  I am worried that I have lost a lot of data. Once I get the data back, I will figure out why the synch is not working.  But, I need to get the data back.