What input are you giving the test? Can you provide one thing you submitted that doesn't work?
Anything in the ARIN region fails. For example, let's take devcentral.f5.com, or 2001:19b8:101:2::f5f5:5
a simple WHOIS query (whois 2001:19b8:101:2::f5f5:5 @whois.arin.net) gives:
# Query terms are ambiguous. The query is assumed to be:
# "n 2001:19b8:101:2::f5f5:5"
# Use "?" to get help.
# The following results may also be obtained via:
American Registry for Internet Numbers ARIN-002 (NET6-2001-1800-0) 2001:1800:: - 2001:19FF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF
Tierpoint, LLC TIER6-3 (NET6-2001-19B8-1) 2001:19B8:: - 2001:19B8:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF
# available at: https://www.arin.net/whois_tou.html
So, you can query the network using the handle:
whois "n ! NET6-2001-19B8-1" @whois.arin.net
Neither of these WHOIS results work with the HE test. I've just been using other regions.