@onlydole, I was getting the response from Vultr and saw it in a Terraform Cloud run frontend, here it is:
And after I whitelisted all IPv4 addresses in my Vultr account everything worked:
It turns out that the IP addresses highlighted in red are wrong, I took them here https://app.terraform.io/api/meta/ip-ranges
Could you please tell me where can I get the correct IP addresses which are used by Terraform Cloud runs?