hiveinvite.com is a service to invite people to hive and create an account for them without compromising on key security, by only revealing the keys to the new user.
I announced the switch from plain keys to keychain a while ago, but there have been user reports of the actual account creation not working.
The issue has been identified, there was a small error in the keychain documentation and I just assumed it to work without proper testing. Sorry for the inconveniences.
You'll now be able to create and send invitation links and create the accounts all with the safety provided by hive keychain. You still need to bring your own account creation tokens, which can easily be acquired through peakd.