The correct spelling is ශ්රී ජයවර්ධනපුර කෝට්ටේ, which can transliterate into the English alphabet in a few different ways. We accept several spelling variants.
It would be nice if the spelling of Sri Lanka's capital that is accepted by the Countries and Capitals of the World quiz were accepted here. That spelling is "Sri Jayawardenpura Kotte." I literally tried every variant I could think of and still didn't get it, which was rather frustrating, as I knew it and just didn't know what spelling to use.