Can't Sign Up for Okta Workforce Identity: "This subdomain is not available"

I am unable to sign up for Okta Workforce Identity trial at Okta Free Trial Account - Workforce Identity | Okta

Screen Shot

Even changing the Okta subdomain doesn’t fix the issue.

Screen Shot 1

I have checked with everyone in my company. Nobody has signed up for Okta. Nobody has claimed this subdomain.