Why các not cho?
Why not 'chúc mừng cho bạn'?
Hints suggests 'cho', but if you put that in it's zapped.
It's accepted without các now.
No its not
Yes it is:
chúc mừng bạn
Các shows that it is a plural form of "you"
But plural is not necessarily indicated by the English.
My girlfriend and her mother always say "chúc bạn mừng".
Congratulations to ALL OF You - các bạn. Either fix the translation or accept the singular version of you.
This is not clear. There is no indication that the "you" is plural. I wrote Chuc mung cho ban. (without accents here)
They won't accept cho. Just chúc mừng bạn or chúc mừng các bạn. Picky program. Won't accept xin chúc mừng either.