"Vanya, where are you?"
Translation:Ваня, ты где?
No Russian would say this, so it can't be perfectly valid translation. Usage is also part of the language, not just grammatical technicalities. Of course you could put Vanya and vy together, but you need a really good reason for that, e.g. humourous use, otherwise it's just wrong.
I don't know if you know any other languages, like Spanish or French, bc that might help understand this. The difference bw formal and informal in these languages IS a matter of grammar. There's a different conjugation used. If you are using a familiar/informal form of a name (Vanya) thrn you need to use the informal address.
So even though Estonian and English alphabets overlap significantly, in Russian class, if i were to translate Ваня as Vanya, the teacher would ask me why i just didn't write Vanja. Weird, having to use the English way of converting Cyrillic, when i'm used to the Estonian way, which makes a lot more sense to me for obvious reasons.
Using вы instead of ты is graded as a typo on the tile exercise. Either it's wrong and should be marked wrong accordingly (in which case there'sa bug in the grading system), or it's correct and shouldn't be marked as a typo (in which case either there's a bug or it's missing from the list of answers). I'm not sure which but I'm guessing the former from other discussion here.
Screenshot in case it's useful :