Getting Cloudflare 521 Error After Upgrade to 3.5.0.beta8-dev

Cloudflare now privide Certificates that valid for up to 15 years, mine is still within the valid period.

That said, just to be sure, I also tried generating a new certificate and replaced the existing one, but I still got the same problem.

If I want to switch back to the default setup using Let’s Encrypt,
is it enough to simply:

  1. Uncomment this line in app.yml:
- "templates/web.letsencrypt.ssl.template.yml"
  1. And set Cloudflare’s SSL mode to Full?