hn has two servers at m5hosting which according to their FAQ [0] "IPv6 support is currently available for Dedicated Servers or Colocation." so you ask support,

hn has two servers at m5hosting which according to their FAQ [0] "IPv6 support is currently available for Dedicated Servers or Colocation." so you ask support, they assign you a prefix and you add a few IPs from that prefix. done. My guess is their anti spam or something else in the software expects an IPv4. [0] https://www.m5hosting.com/support/cloud-faq/ https://www.m5hosting.com/support/cloud-faq/