Yes I did update the redirect/challenge block as you gave me. Thanks for that.
I agree - I also suspect that my compile of nginx contains the fault. Further I suspect it is in openSSL, but the maintainer has not responded to pleas for help.
nchan is a module to pass messages from one visitor to another, and run a chat room. The code using web_rtc for the heavy lifting, (audio and video) and that requires SSL.