Issue creating account on

My employer created an account on for testing purposes. A domain name on has not yet been set up for that account.

When I log in to that account, it shows me the following screen:

Let's get started

You'll need an account before you can deploy any applications. Account names can contain letters, numbers and hyphens, but can't start with a hyphen or a number, and can't end with a hyphen. Pick an account name below to proceed.

And it shows a text box for entering the domain name. When I enter any domain name and click "Save", I get the following error and I cannot progress any further:

Request Validation Error: : field 'name': is invalid account name