Could it be ?
Given the phrase length: danlwd fyltr shkn qwy tap wy py an danlwd fyltr shkn qwy tap wy py an
danlwd ROT13 = qnayjq (no) fyltr ROT13 = sl yge — not good. Could it be
Alternatively, a : “danlwd fyltr shkn qwy tap wy py an” might be ROT13: danlwd fyltr shkn qwy tap wy py an