As far as I checked, looks like domain nameservers are okay.
Returned IP address of Website A record is Cloudflare and is proxied , DNSSEC has no issue.
Furthermore, if you recently changed your domain nameservers, regular DNS propagation time usually takes up to 24-48 hours to complete.
You could get this error even as there might be some DNS cache at your local ISP provider.
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)?
Great, thank you very much, seems to be resolved.
Can you please tell me what it means is it is proxied or not? what is the difference? and what would be better?
When it’s proxied, your original ips are hid behind Cloudflare IPs. Traffic is served through Cloudflare protecting your origin server; and more features you benefit from by keeping proxied. While is not recommended unless there’s a specific need. More info is here: