Errors with IPv6 only NAT64

[miyurusankalpa]

1. Uses NAT64 for IPv4 checks

Traceroute for ultra low latency primary IPv4 (64:ff9b::d992:b31)

2. Does not skip IPv4 checks.

Fetching PoP name for ultra low latency primary IPv4 (ipv4.dns1.nextdns.io)
  anexia-maa: 249.99ms
Fetching PoP name for ultra low latency secondary IPv4 (ipv4.dns2.nextdns.io)
  do-blr: 175.933ms
Fetching PoP name for anycast primary IPv4 (45.90.28.0)
Fetch error: Get "https://dns.nextdns.io/info": dial tcp 45.90.28.0:443: connect: network is unreachable
Fetching PoP name for anycast secondary IPv4 (45.90.30.0)
Fetch error: Get "https://dns.nextdns.io/info": dial tcp 45.90.30.0:443: connect: network is unreachable
Fetching PoP name for ultra low latency primary IPv6 (ipv6.dns1.nextdns.io)
  anexia-maa: 395.796ms
Fetching PoP name for ultra low latency secondary IPv6 (ipv6.dns2.nextdns.io)
  do-blr: 386.427ms
Fetching PoP name for anycast primary IPv6 (2a07:a8c0::)
  vultr-sjc: 253.314ms
Fetching PoP name for anycast secondary IPv6 (2a07:a8c1::)
  anexia-lax: 232.599ms

3. At the end post gets failed.

Post unsuccessful: status 400

Script should check for DNS64/NAT64 and handle it accordingly.