Hi,
Sorry for the issues you are having. I can help troubleshoot this with you.
So it appears the Facebook Page that created the event:
https://www.facebook.com/themojamoja/
Has some kind of restriction, it might be by country or age and that is preventing the importing.
That page would have to change their restrictions to be able to import the event, Facebook does not provide us any other way to get around this unfortunately.
Let me know if you have any follow up questions.
Thanks