dHCP login failure

Hi, I attempted to download data from dHCP, but I’m having a trouble with logging in to the dHCP website.
I’ve entered username and password correctly, but it says :

" Your login attempt failed because the username and password combination you provided was invalid or your user already has the maximum number of user sessions open. After 5 failed login attempts, your user account will be locked. If you believe your account is currently locked, you can:

  • Unlock it by resetting your password
  • Wait one hour for it to unlock automatically "

I’m sure I entered correct username and password,
and tried less then 5 times.
Also I’ve waited more than an hour for automatic unlock, for several times.
I can’t even find ‘resetting password’ button, and I don’t think it would be even possible before logging in…

What else can I try?
Is there a way to ‘unlock’ my account - if it is locked?

Would there be any chance that the problem started from the register process?
When I filled in every required blanks and pressed ‘OK’ or ‘Next’ (not sure) button, the page had just freezed.
After that I could see that my email account was registered because when I tried to register again, it said that my email address already exist.

Thank you for reading this and your kind replies.
Best, Yeri