Hi Vincent,
I’d like to confirm if you have added and verified the domain in Online Portal. I have checked the DNS record for the domain and found there are no any DNS records which relate to Office 365. If you haven’t added/verified the domain in Office 365, I suggest you add and verify the domain. For more information regarding add and verify domain, please refer to Add your domain to Office 365.
If you have already added and verified domain in Office 365, please check if the domain has expired.
Thanks,
Kent Gu