I tried to reproduce this but was able to successfully create a tenant and see my default directory. If you are trying to create a B2C directory rather than a regular directory, you need to have a subscription associated with the account. If you are trying to create a regular Azure AD tenant, I would recommend testing with a different account and seeing if you still run into this problem.
If the tenant name is already taken and you own the tenant that has that name, you can either restore the old tenant name or create a new tenant with a new name. (You would have to remove the domain from the other tenant first and then verify it in the new tenant.)
If you are still having this problem after trying these steps, feel free to reach out to me (email included in private comment), and I will get a support case opened for this.