Microsoft on-premises server product that runs Office Online.
I apologize for the inconvenience this has caused.
I've tried to access the service from my side and am seeing the same "Office Online services aren't available right now" error. I've also noticed reports from other users experiencing similar issues with the Office Online Viewer service. For example, Office Online services aren't available right now - Error when opening Word documents through web-ba…
At this time, however, I have not found any official communication, service advisory, or incident notice published by Microsoft regarding this issue. The public service health page does not currently provide a specific notice for this behavior.
As a normal forum user, I do not have access to the backend system, therefore, I cannot provide you the estimated time the service will be back online.
My recommendation is to open a support ticket with Microsoft support team via https://engagecenter.microsoft.com/#home. They will be able to investigate further on this issue.