After applying Cloudflare on the web app domain (provided also by Cloudflare) reached a problem when the proxy status for DNS records was on (view image 1).
App deployed on Railway can't be reached (image 3). Also, the railway custom domain is hanging on the "Cloudflare proxy detected" status (image 2).
But when the proxy is off everything works as supposed. As we researched proxy could not be turned off if we wanted to use a whitelist IP firewall and captcha.
Hope to see your answer soon, thanks for your attention to my issue.