An error occurred while updating the calendar event
Since I know of no method, how to delete multiple events matching some condition.
The only way I could figure this out, is to select all of those, and update them one by one, which could be a bit of problem since you can: If you edit an instance, then it wont be shown as an instance to the recurring event.
There was a problem with the server configuration changes.
You can continue using the application, but may experience difficulties, including the inability to save changes.
Please contact your Dynamics 365 administrator and give them the information available in ‘more information’.
How to troubleshoot scenarios when you are unable to open a file or folder on a local drive on your computer.This can occur if you don’t have permissions on the file or folder, or if the file has been encrypted Troubleshoot "access denied" when opening files or folders This article desribes how to resolve common problems with accessing files or folders.