Four checks, about a minute, and you will know whether to change a setting or simply wait.
Another address works → a block. Use that address, and change your DNS if you want the original back.
No address works, but other sites do → likely a network-wide block. Change your DNS first.
Nothing works anywhere → your connection, not the site.
Every address gives a server error page → a real outage. Waiting is the only fix; it is being worked on.
Treat them loosely. They check from outside Bangladesh, so they will report a site as perfectly healthy while it is blocked for every user here — and that is the exact situation you are trying to diagnose. The four checks above test your actual route, which is the thing that matters.
One thing worth ruling out: make sure the address you are testing is genuinely ours. A look-alike going offline says nothing about the real site — compare against the official list first.