All-time I'm getting this error when I create a first-time event. The second time and afterward it's worked fine.
although I'm giving start and end date correctly. I attached the error screenshot with this.
This error suggests that the event data object doesn't have the correct structure.
I recommend checking the object - it may look fine at first sight but make sure that it's a real object - and not a JSON string or an array, for example.
I checked and It's a real object.
Thanks for the update.
If you check the object structure you can see that it doesn't include the required properties - id, start, end, text and resource are missing.