The problem is that your DNS configuration for the domain is invalid. You need to fix that at CloudFlare (i.e. at the level of your authoritative DNS service) - it is not a problem with your Mac.
The problem with your DNS configuration is that your domain, webtop.blog, is advertised to be protected by DNSSEC - but it is not setup.
In simple terms, DNSSEC is used to ensure integrity of DNS responses by using cryptography to sign DNS records at each level of DNS lookups. This ensures that others cannot suddenly takeover your domain and start publishing records for it (for example in a man-in-the-middle attack on a specific network) - DNSSEC-enabled systems would detect that the modified DNS records do not have the right signature, and the lookups would fail.
In your case, you have setup CloudFlare to send out DNS responses for your domain - such as for example A records with IP addresses for your web server. However, you have not setup CloudFlare to send out DNSSEC records.
This means that the domain fails DNSSEC validation.
Some systems do not understand DNSSEC or purposely do not validate it, and on these systems your domain will work.
On other systems, such as for example Google public DNS (188.8.131.52/184.108.40.206), a failure to provide the correct DNSSEC records means that all lookups will fail.
You can find a guide on how to add DNSSEC records to your CloudFlare DNS here:
You can see that your domain is setup for DNSSEC at the registry by a simple DNS lookup from your Mac:
dig -t ds @a.nic.blog webtop.blog
You'll find that the reply contains a DNSSEC as listed here:
webtop.blog. 3600 IN DS 16264 8 2 2876E6FCB382D01DDDBEBD7B5DF48D5BF261A4F852DB918CC1AAE1E5 172163E6
However, when asking for the DNSSEC records from CloudFlare like this:
dig -t ds @logan.ns.cloudflare.com webtop.blog
You'll get no records.