Checking your Mail box usage

You can check your O365 mailbox quota and usage in the "Options" of Office 365 Outlook Web App (OWA):

1.   Login your O365 account at office365.stfx.ca
2. Open your mailbox by clicking the outlook mail icon
3. Click  (gear) icon at the top-right corner of OWA window.
4. Select Mail under Your app settings.
5. Under the General heading select My Account
6. In the bottom right corner there will be a visual for your mailbox usage 

Mail will no longer send once mailbox storage reaches 49.5GB