nginx can’t find /etc/letsencrypt/options-ssl-ngin.conf file

I’m trying to serve a python-django webapp using a linux box (running ubuntu 18.04) with nginx, gunincorn, letsencrypt and docker. After following a number of online tutorials I have been successful in serving the app via http through port 80 by following this tutorial http://pawamoy.github.io/2018/02/01/docker-compose-django-postgres-nginx.html. However, I am now really struggling with deploying via https…