PowerShell registration problem

Hi,

I've got a problem with registering users for password reset in FIM - they are created in FIM Portal and they are populated with accountName, Domain and ObjectSID attributes.

I don't have registration portal as my company doesn't need to use this - instead of we have OTP SMS gate. I wanted to test registration of one account through script listed in TechNet article: Register-AuthenticationWorkflow

But I have "Denied" status thrown on "Create GateRegistration (...) Request". Why is that so? I am an administrator...