Microsoft on-premises server product that runs Office Online.
If you're referring to Microsoft's ongoing service incident (Incident ID: MO1550821), which is affecting multiple Microsoft 365 services, including Exchange Online, Microsoft Teams, and SharePoint Online, Microsoft is still working to restore the affected services. However, Microsoft has not yet announced a confirmed estimated time for full service restoration.
If you are a Microsoft 365 administrator, you can check the Service Health dashboard in the Microsoft 365 Admin Center for the latest updates on the incident and its recovery progress.
If you're an end user without admin permissions, kindly reach out to your organization's IT administrator for assistance. If you're unsure who your Microsoft 365 administrator is, you can find guidance here: How can I find my Microsoft 365 admin? - Microsoft Support