My guess is something (perhaps your ISP) is redirecting your DNS queries. I just tested this and it is working fine.
┌─[lawrencet@poptop480]─[~]
└──╼ $dig @1.1.1.3 pornhub.com
; <<>> DiG 9.11.5-P4-5.1ubuntu2.1-Ubuntu <<>> @1.1.1.3 pornhub.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 16190
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1452
;; QUESTION SECTION:
;pornhub.com. IN A
;; ANSWER SECTION:
pornhub.com. 60 IN A 0.0.0.0
;; Query time: 22 msec
;; SERVER: 1.1.1.3#53(1.1.1.3)
;; WHEN: Tue Apr 07 06:47:39 EDT 2020
;; MSG SIZE rcvd: 67