Furthermore, if you recently changed your domain nameservers, regular DNS propagation time usually takes up to 24-48 hours to complete.
May I ask have you tried using a different Web browser, or tried clearing your Web browser cache?
How about using a Private window (Incognito mode) or a VPN connection if possible?
Is it the same behaviour on your mobile phone (4G LTE, mobile data, cellular)?
May I ask, if you know was the DNSSEC active and enabled for your domain name at your Domain Registrar, before switching domain nameservers to the given Cloudflare nameservers of your Cloudflare account?
Was DNS records set correctly?
Before moving to Cloudflare, was your Website working over HTTPS connection?
Have you tried using any of the available online tools for DNS propagation check for your domain name yet? For example: