It looks like there is indeed an error when you try to submit a new event. However it's not clear from the log you providied what exactly is going wrong.
Can you please confirm if you are able to retrieve calendars and/or events from the second account or if it's only when adding events that an error occurs?
For the first calendar I can retrieve the calendar items
For the second the Items is empty.
The ShowMessage(AktivCloudGCalendar.Calendars[0].ID ) ; shows a very strange ID (not my email address) : 'tvsqjcfk73aaa64j3699diooik@group.calendar.google.com'
In the log (only) I can see some events which are not in my calendar. E.g:
We are not aware of such an issue in TTMSFMXCloudGCalendar and also haven't received any similar reports from other users so it is possible this issue is caused by a specific configuration of the Google account.
Can you please send the full log file along with exact steps to reproduce the issue by email (mailto:help@tmssoftware.com) so we can further investigate this issue?