I don’t think it’s an issue on our end. The error message suggests there is a problem with the DNS lookup of your domain, but a DNS checker tool says that your domain is resolving correctly from everywhere: DNS Checker - DNS Check Propagation Tool
It seems most likely to me that something on your end is blocking the domain name. Our domains do sometimes end up on blocklists which may impact some people’s ability to access websites on free subdomains.
You could try contacting your internet provider or network administrator about this and see if they know more about this.