Again its not about you getting to the site or not - its the fact of resolving it... That site is also cloudflare dns..
Can you not resolve it?
$ dig www.improbable.com
; <<>> DiG 9.16.1 <<>> www.improbable.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4181
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www.improbable.com. IN A
;; ANSWER SECTION:
www.improbable.com. 3600 IN A 104.27.163.33
www.improbable.com. 3600 IN A 104.27.162.33
;; Query time: 71 msec
;; SERVER: 192.168.3.10#53(192.168.3.10)
;; WHEN: Wed May 06 12:52:48 Central Daylight Time 2020
;; MSG SIZE rcvd: 79
here is trace
$ dig www.improbable.com +trace
; <<>> DiG 9.16.1 <<>> www.improbable.com +trace
;; global options: +cmd
. 81565 IN NS h.root-servers.net.
. 81565 IN NS b.root-servers.net.
. 81565 IN NS j.root-servers.net.
. 81565 IN NS e.root-servers.net.
. 81565 IN NS c.root-servers.net.
. 81565 IN NS d.root-servers.net.
. 81565 IN NS m.root-servers.net.
. 81565 IN NS g.root-servers.net.
. 81565 IN NS a.root-servers.net.
. 81565 IN NS l.root-servers.net.
. 81565 IN NS i.root-servers.net.
. 81565 IN NS f.root-servers.net.
. 81565 IN NS k.root-servers.net.
. 81565 IN RRSIG NS 8 0 518400 20200519050000 20200506040000 48903 . b3rDX8hw+NlEeGXwx0uYMKtwjStmSBgr6EdkvQxqhrTHRpqyfywF0Du6 5Vy0XT9nq54eqDfK1AvD7q8rH/qc+mpd5TQoQdkpCW0wad1tZsnnwwFr VUq7H+LM3FBXc024sZG6ha7MZpdm3rDIEF1QpVjgbWpfEqEqIh9qUzlG gnKm8c9ZJLDZ8GV8bAO42miSRjaMgipCcQkZ6FZru8WFo7XiGJ+lUkpQ OIBLMm55LR5zwF4/0+Zu+fXZIay9+9S2CbPwscWqfZnJUzBCXt/Xsjdq u97c5MM2hV3wmlYRlsubnKER5RDZYJDSsKwipJekfsgo6nGo5TD2PWM8 aT82pg==
;; Received 525 bytes from 192.168.3.10#53(192.168.3.10) in 3 ms
com. 172800 IN NS a.gtld-servers.net.
com. 172800 IN NS b.gtld-servers.net.
com. 172800 IN NS c.gtld-servers.net.
com. 172800 IN NS d.gtld-servers.net.
com. 172800 IN NS e.gtld-servers.net.
com. 172800 IN NS f.gtld-servers.net.
com. 172800 IN NS g.gtld-servers.net.
com. 172800 IN NS h.gtld-servers.net.
com. 172800 IN NS i.gtld-servers.net.
com. 172800 IN NS j.gtld-servers.net.
com. 172800 IN NS k.gtld-servers.net.
com. 172800 IN NS l.gtld-servers.net.
com. 172800 IN NS m.gtld-servers.net.
com. 86400 IN DS 30909 8 2 E2D3C916F6DEEAC73294E8268FB5885044A833FC5459588F4A9184CF C41A5766
com. 86400 IN RRSIG DS 8 1 86400 20200519170000 20200506160000 48903 . YyraVh9G5c5nXgKNPGsh72KnhrzpuZ5Hn55AQ7QT60SQbfxPFYN1y3D0 iySMImGx6EWg7rpxwsq/XrCyE415G2SfFzSJu27/PfgI5itPmlDeaksK DCiPDAh24ps5F8dA1gs5bEhXg6v1I4Bs9utYjVgZ//4DdlA6hUsOK41t QgWa2PDNJncShftRKwxKZbFq3b1CTvpFywIQz0WHCDfaqR1wN+wYxPrK XzpHN4Pht+9j/faQmdTBUZchCQG0/ki+Xv1ZIQ2FsfKfPK2Q+vlwYoa3 T6P3IKu6R/iM+i7i3WEkTb7mX+HC3/0YQqQotDQ51kcH0sOkzs40L+3P m03r/w==
;; Received 1178 bytes from 199.7.91.13#53(d.root-servers.net) in 12 ms
improbable.com. 172800 IN NS lee.ns.cloudflare.com.
improbable.com. 172800 IN NS edna.ns.cloudflare.com.
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN NSEC3 1 1 0 - CK0Q1GIN43N1ARRC9OSM6QPQR81H5M9A NS SOA RRSIG DNSKEY NSEC3PARAM
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN RRSIG NSEC3 8 2 86400 20200513044951 20200506033951 39844 com. DQ9LaY7nv4abiSkEn0gpiP0cQ8J7yqT4l29DPEUyTure4dT/cQOGGhB4 YaB6r/2IAy0Q32WN2JIPrBQZWYFans5vdqZKOE0bT5WIOCK3TFqfmpKy wcaRIcAqloo2ucXB5WSk30r4+ep3DgkfgQyAmgDfJWM0jMEMPxRYhm3l DBVkbvRe4un6nc1i07mz7d1i25O8nmx24r929EcMKPlF4w== 3I65V3ONV364ETJ2N1O9QUJPSL5CIF78.com. 86400 IN NSEC3 1 1 0 - 3I672DQ9VK3GG4PH2A6ALH81124LCHFC NS DS RRSIG
3I65V3ONV364ETJ2N1O9QUJPSL5CIF78.com. 86400 IN RRSIG NSEC3 8 2 86400 20200513052416 20200506041416 39844 com. jBWZ6lII936oHQstMrhhjdBd4s9htotlcd/OoB7/uJqZKMNcvU8kgrc7 Pq56BylJdf3IPPCQoNQB46scFOxQDI2HHgU8dQVnNe5yVvVjL6nk4hrY qPZ+NQlk8DP7ej5fEdbLB01zYe9iiAvAHgE1K7k1ygn4kDZXQmkM2v/N P+Jb2o6TRM4NeatDghxTmh2ST1XHP/zd8Vv2OoQASH4oJQ== ;; Received 735 bytes from 192.5.6.30#53(a.gtld-servers.net) in 31 ms
www.improbable.com. 300 IN A 104.27.162.33
www.improbable.com. 300 IN A 104.27.163.33
;; Received 79 bytes from 173.245.58.109#53(edna.ns.cloudflare.com) in 25 ms
The site could be utter crap.. That is not the point.. There is one thing if he was using dns that did "filtering" and blocked it because it had xyz, or whatever.. But he is resolving, and trying to talk to the authoritative ns for that domain. Its not the ISP place to filter dns, unless they want to do that via their dns servers... He is trying to talk from his IP to some IP on the internet on port 53... Not his isp place to filter that, if that is what they are doing because they don't like whatever sites that NS my resolve..