I suggest you change the hint from 'actual name' to 'official name' for clarity. Also, do you really except the quiz taker to type in exactly 'green, white, and red', for the extremely vague hint for 'big things in Mexico', 'culture, bright and vibrant colors, tradition?'
I put the name as Estados Unidos Mexicanos which was not accepted. I put the colors of the flag as red white & green which was not accepted. For big things, I put mountains, Mexico City & earthquakes, none of which were accepted. Stupidest quiz on jet punk.