Unable to access my website after changing host

Hey guyz, hope you are doing fine, i need some help please, last night i have changed the hosting for all of my sites, every site is working fine except 1, it appears error like,

“Server not found

Firefox can’t find the server at zahaq.com.pk.
Check the address for typing errors such as
ww.example.com instead of
http://www.example.com
If you are unable to load any pages, check your computer’s network
connection.
If your computer or network is protected by a firewall or proxy, make sure
that Firefox is permitted to access the Web.“

I was using BBS bulletproof-security before, now i had delete it and restore all .htaccess files. But still appears the same error. Your help needed please 🙁