But it should rather still be accepted. We aren't here to learn English, and it's annoying for it to be marked as incorrect when it's still obvious that it was understood.
Maybe there are rare cases where it matters; but for most cases, writing "do not you" instead of "don't you" shouldn't matter. The same goes for other errors like "these dogs is brown".
I know it's incorrect English, but we're not here to learn English.
English grammar is weird. :)
When you have a negated yes-or-no question like that, the proper order is "do-subject-negation-verb". So you need to write "Do you not know good actresses?" Oddly enough, contractions are able to skip that subject, so you can also say "Don't you know good actresses?"