I wasn’t clear, sorry. It did not work in any of the mobile browsers. It did work in another browser on my laptop.
Excellent. good to know. I’m glad you got it working! 
But I haven’t. I only got it working in another browser in my laptop. It still fails in my smartphone.
Oh now I misunderstood you - I thought you meant when you switch browsers it suddenly worked on your phone. 
Ok so you have 2 browsers on your laptop that can do it, but no browser on your iPhone can enable encryption?
Correct. Nor in the Discourse App (althought I guess it is just a wrapper around the same engine that Safari uses).
Discourse Encrypt는 비추천(deprecated) 처리되었습니다 더 이상 meta에서 해당 플러그인의 이슈를 추적하지 않습니다.
여기서 작업을 진행하려면 제3자 플러그인이 생성되고 유지 관리되어야 합니다(전용 플러그인 토픽에서).