Does your ISP or DNS resolver have a service that blocks malicious sites? Some of them will block all of InfinityFree’s free subdomains.
You might want to try accessing your website on a different network or while using a VPN. If you can do that successfully, that means it’s definitely an issue related to your network.
Since your error message says the site couldn’t be reached that’s likely unrelated. But it’s a good idea regardless.