Office 365 cannot receive mail, error 550 - Mailbox unavailable

Hello,

I have started using Office 365 and added a domain there (pinassi.fi). Now email cannot be sent to pinassi.fi addresses, an error message like

<ari.rosti@pinassi.fi>:

216.32.180.190 does not like recipient.

is replied to sender.

The domain is verified and DNS records are ok. I have tried everything I have found in troubleshooting scenarios and forums, but nothing seems to help. Now what can I do, these email addresses are business addresses to us!