N. jamban likes cool temps and high humidity. It comes from Sumatra (which is generally a warm place), but up in the mountains, where it stays cool. It appreciates the same conditions ex-situ. Other Sumatran neps from below the mountains in warmer conditions will grow much better if hot.
Like hungrycarnivores said, there are a lot of other species with toilet-bowl shaped uppers that are less picky. I grow N. pitopangii "ivory colored form", which has cute, red lowers and white, toilet-bowl shaped uppers. It seems to be more vigorous and less picky than jamban. There are also jamban natural hybrids with other small Sumatran species (dubia, inermis, etc.) that are much more vigorous and less spendy. Native Exotics has a super nice specimen of jamban x dubia up for auction right now-
https://nativeexoticsonline.com/product ... s-wistuba/