"Please give me two sheets of paper."
This is a problem I find with a few other questions as well, and it's that it only accepts certain kanji but not others, much worse in this case since when I type 「にまい」, I either get the hiragana or 「二枚」, the full kanji, but it doesn't accept either of those as correct, therefore forcing me to have to write 「二枚」, and then go back to change the 「枚」 to 「まい」.
Verbs that come before "kudasai" are conjugated in the -te form, so that's why you're used to seeing "te" before "kudasai". Nouns take the particle を before "kudasai". In this question, we have a counter, 2枚 (2 mai). Counters don't usually take particles and they don't conjugate, which seems strange but is correct.