This is not a SFW instance. NSFW communities will be tagged, and efforts will be made to keep SFW communities clean, but proceed at your own comfort level.
And I can apparently ping it! So maybe it isn’t DNS?
$ ping6 2620:00fe:0000:0000:0000:0000:0000:00fe
PING 2620:00fe:0000:0000:0000:0000:0000:00fe (2620:fe::fe) 56 data bytes
64 bytes from 2620:00fe:0000:0000:0000:0000:0000:00fe: icmp_seq=1 ttl=60 time=6.69 ms
64 bytes from 2620:00fe:0000:0000:0000:0000:0000:00fe: icmp_seq=2 ttl=60 time=5.53 ms
64 bytes from 2620:00fe:0000:0000:0000:0000:0000:00fe: icmp_seq=3 ttl=60 time=5.93 ms
64 bytes from 2620:00fe:0000:0000:0000:0000:0000:00fe: icmp_seq=4 ttl=60 time=8.51 ms
So I’m using this one:
2620:00fe:0000:0000:0000:0000:0000:00feAnd I can apparently ping it! So maybe it isn’t DNS?
Quad9 is not a bad choice, maybe its a IPv6 connectivity issue? Have You tried it via IPv4?