Admin for .tk (not a spam/abuse complaint!)

[Tim Harman via NANOG <nanog () nanog org>]

Hi,

If anyone has contact details for the operators of the .tk TLD, could 
you contact me off-list please?

We are unable to contact the authoritive NS for this TLD - it seems our 
range is on a blacklist or they have some odd route back to us that 
isn't working.
Thus our customers can't resolve any .tk names.

I've tried mailing a few @dot.tk (from a host that has no trouble 
resolving the domain!) but have heard nothing back.

Specifically after a contact for whoever maintains

;; ADDITIONAL SECTION:
a.ns.tk.                172800  IN      A       194.0.38.1
b.ns.tk.                172800  IN      A       194.0.39.1
c.ns.tk.                172800  IN      A       194.0.40.1
d.ns.tk.                172800  IN      A       194.0.41.1

{11:58}~ ➭ dig @194.0.41.1 test.tk

; <<>> DiG 9.11.5-P4-5.1+deb10u5-Debian <<>> @194.0.41.1 test.tk
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

Many Thanks,

Tim