Routing on the Internet relies on the Border Gateway Protocol (BGP). BGP distributes routing information and makes sure all routers on the Internet know how to get to a certain IP address. When an IP range becomes unreachable it will be withdrawn from BGP, this informs routers that the IP range is no longer reachable.
For example, one of the name servers for the DNS zone .SY is ns1.tld.sy with IP address 18.104.22.168.
Normally our routers would expect a BGP route for 22.214.171.124/18
Currently that route has disappeared and we no longer have a way to reach the Nameservers for .SY that reside in Syria