If you check whatsmydns.net, you will see the domain is pointing to the IP address 199.59.243.225. If you check your account information, you’ll see the IP address of your account is 185.27.134.24. So the subdomain is resolving, yes, but not correctly, because it’s pointing to your hosting account.
The reason for that was clearly pointed out by @dan3008: the domain name is no longer present on your account. It looks like it was immediately removed after creation of your account.
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