Why do I see "No Data" for the performance metrics under my Office 365 monitor?
Data collection for Office 365 takes place only once in a day. That's the reason for the message "No Data" under Sites, Domains, Exchange, Skype, and SharePoint, if the data collection had happened before 24 hours. To view data, select the time frame as Yesterday or to an older time span and try again.
Note: If the data collection had happened 24 hours back, the time frame Today will show stats only for Service Health and Inventory.