Remake the format (context --make en) or delete the font entries (uthmantn1-ver10.tma|tmc) in the cache ($TEXMF/texmf-cache/luatex-cache/context/<HASH>/fonts/otl/). Please try both suggestions and report which of them helped.21. August 2016 um 12:53Hello,The code snippet at the end used to work a few months ago when I reported a rendering bug. But now the font does not load and I see the following error. (It's not an issue with simplefonts because \definedfont[KFGQPCUthmanTahaNaskh*arabic] does not work either. the font is published here.