@Manal Aquil, 

Out of curiosity, in your "setting" for the knowledge Article artifact, has the tickbox for "Enable Projects" been ticked? If it has, try unticking it and requesting the article again. If it is that, it's because you haven't got a Project to associate to, and that feature is when you want to do say a whole KB or a whole Catalog as a single project to release the translations for use at the same time,

Many thanks,
Kind regards