My book is totally fantasy, full of made up countries and places, all with fictional names I created, but most of my characters have real names. Some are English, others are Asian, and some are even African, since the world is pretty big and I didn't want all of the names to have the same nationality. I don't know if this is actually a problem, since none of the people that have read my drafts ever said anything about names, not even about the harder ones, but I think it's worth asking.
Should my book have only invented names, or is it okay to have a mix of both? And should I avoid Asian/African names, since they are harder to pronounce?