Here I am again.
I tried some calendars (Event organiser) but they won’t display in the widget sidebar.
I figured, maybe this is because they are not compatible with the theme?
Or is it something else? http://www.royalwebdesign.nl/vcmajella/
Most likely you have wrong date/time for you hosting/WordPress instalation or events you added are already expired. I am certain that this is not related to theme
This is old thread ans to help us keep support thread separates could you please create your own thread for your question here https://colorlibsupport.com/c/sparkling/ instead of replying on others thread as it makes the thread messy and hard to read.
If you want to you can also add reference of this thread in your newly created thread.
We would be more than happy to help you on your new thread.