i have registered but when i click to the confirm in the validation email i get this message:

ERROR OCCURRED
Sorry, but we are denying you account creation. Could not authorize transaction.

what could be the problem?

Well if you are trying to make an account for International HoN and you live outside of the countries they will deny it.

In other words if you are a turk, middle eastern, or any foreign countries you wont be able to play on our client.

Sometimes, if you've created multiple free to play accounts, your request will be denied. Waiting a month will fix this issue.