Zoho developer edition does not work for us

Is anyone else having this problem?

I'm signed in with our admin/super user account.

When I click on the link on this page:

I am asked to agree to Terms and Conditions.

Clicking Agree to Terms and Conditions just refreshes the page. I can't go any further.

We contacted support, but this was their reply (unhelpful):

If someone is invited through as developer through sandbox account then this developer edition would be visible.

You can login through developer.zoho.com that should work.

If I am using our admin account, why do I need to be invited? "Sandbox account" is not mentioned on the developer edition page.

Best regards,

Marcus