1.1.1.1. not working

The nameservers for 51talk.com don’t respond to queries when I test directly or 3rd party tools.

http://dnsviz.net/d/sso.51talk.com/dnssec/

dig sso.51talk.com +trace @8.8.8.8

; <<>> DiG 9.11.1 <<>> sso.51talk.com +trace @8.8.8.8
;; global options: +cmd
. 50054 IN NS a.root-servers.net.
. 50054 IN NS b.root-servers.net.
. 50054 IN NS c.root-servers.net.
. 50054 IN NS d.root-servers.net.
. 50054 IN NS e.root-servers.net.
. 50054 IN NS f.root-servers.net.
. 50054 IN NS g.root-servers.net.
. 50054 IN NS h.root-servers.net.
. 50054 IN NS i.root-servers.net.
. 50054 IN NS j.root-servers.net.
. 50054 IN NS k.root-servers.net.
. 50054 IN NS l.root-servers.net.
. 50054 IN NS m.root-servers.net.
. 50054 IN RRSIG NS 8 0 518400 20180413170000 20180331160000 41824 . PkLVV5D4q3MuzxEXYeW+SlYvDOJ4E1+j3vB1FgK3rZxZlrBd1IHVUDTi MyI3wTH4vedkF5HEoSTxSpQGMVKN6v2D2X9t5RARslKrf1UYM878V8Vb a5BOQrxTFPR3kjAJqGvKKCe1D48BfmCzs1vzqLqc+384dfUgdz9657TL Ejz0TriRZf9aUMQEMXlWPKbu7BRJdkH3Y1Xk5hTUDDme92D1GCmKoDNj 55Sd0DE7O5Vuc0bGCuUzu9j71Na32TGgmGnrLULXQITALXThVmLBQ4t6 ejuLHpXWBKzIphRuO5VkpnR/Ekj05qf2h5VbtSX18hT5HYzXMpeaD2hf 1mc4oQ==
;; Received 525 bytes from 8.8.8.8#53(8.8.8.8) in 11 ms

com. 172800 IN NS m.gtld-servers.net.
com. 172800 IN NS i.gtld-servers.net.
com. 172800 IN NS j.gtld-servers.net.
com. 172800 IN NS l.gtld-servers.net.
com. 172800 IN NS a.gtld-servers.net.
com. 172800 IN NS g.gtld-servers.net.
com. 172800 IN NS e.gtld-servers.net.
com. 172800 IN NS b.gtld-servers.net.
com. 172800 IN NS c.gtld-servers.net.
com. 172800 IN NS k.gtld-servers.net.
com. 172800 IN NS f.gtld-servers.net.
com. 172800 IN NS h.gtld-servers.net.
com. 172800 IN NS d.gtld-servers.net.
com. 86400 IN DS 30909 8 2 E2D3C916F6DEEAC73294E8268FB5885044A833FC5459588F4A9184CF C41A5766
com. 86400 IN RRSIG DS 8 1 86400 20180416170000 20180403160000 39570 . pJTIe47zCyjukA6T3mgmYyZpQ1aRQVFkmgXRyReaU4eGXCHILI/VqGFh zALzwrBJRe8CPG1OnH4GAJOmgN/smoz9kIJI6PT+mh7p3nddaLQiS2YF EwrUzk8EaJTh5B3A4gE2+HuZOqO82XBK8x10yynxAcODRn0ESH6DW4ST L0UzQG1P62CbS1fQAt6bscf6pHfg8T6awz/204w/wdgGl2crkkbSScHd 9w5Iz7VmHgi0K/UXnIxxJC2FAx4c/SmXEVtt3aDljZMBh/cIFXz28K9Y oNqR2tjqSnEDgCnTXr8wBHQ6jD0HnEoj9Z5aE7vh6on07zWGx3BHErPy Btnecg==
;; Received 1202 bytes from 193.0.14.129#53(k.root-servers.net) in 132 ms

51talk.com. 172800 IN NS dns17.hichina.com.
51talk.com. 172800 IN NS dns18.hichina.com.
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN NSEC3 1 1 0 - CK0Q1GIN43N1ARRC9OSM6QPQR81H5M9A NS SOA RRSIG DNSKEY NSEC3PARAM
CK0POJMG874LJREF7EFN8430QVIT8BSM.com. 86400 IN RRSIG NSEC3 8 2 86400 20180410044734 20180403033734 46967 com. yjm0YT6b7f1lZXtF2MNFz5H9nVRRViVH4d3FlOV8YefucCXLaYm/fkUh Yu9JBcoPqdBLCHnCQ9JuaEbiXZx1QMYplUH0lxTQH+iRkbVUq0MF2DWb DaehQkvF+ANCN58TzNdwpsptsj6KXHi6RC6j4cozl3GpgP6xn55lO8FH 4qE=
BJDPSNQ8RTM2MGUVL84R1DBFGD8S2T3E.com. 86400 IN NSEC3 1 1 0 - BJDRMU45N63D6KPIO1MPVT3361LLCFKK NS DS RRSIG
BJDPSNQ8RTM2MGUVL84R1DBFGD8S2T3E.com. 86400 IN RRSIG NSEC3 8 2 86400 20180407045850 20180331034850 46967 com. vq+KPfHUKjTfE7rGNVBZtCZkLSFyvbeFDtW8qa2KYf11aJzXOtaTekzH wmKkwBaMLMNMlP7PBloj8BF+VUhAoIR7rzxDN2b9n3vXxp/+GG/+yRbV TfYEMWec6FmVpPng5o5yPJqHvVsbdBZds7rxITQG767y1n+bLxoaMiDo j0s=
;; Received 832 bytes from 192.54.112.30#53(h.gtld-servers.net) in 43 ms

;; connection timed out; no servers could be reached