My users cannot log in with Facebook anymore. This is the error log:
(facebook) Authentication failure! csrf_detected: OmniAuth::Strategies::OAuth2::CallbackError, csrf_detected | CSRF detected
I’m using Cloudflare in front of nginx. I’m using Cloudflare automatic SSL (flexible). I didn’t install any certificate on my server (i.e. I’m not using Letsencrypt).
Is this related to Cloudflare? Can this be solved without installing Letsencrypt?