CSU has implemented quotas on Outlook (email) and OneDrive space. If you are having issues with quota messages in either of these programs, please see information available here:
https://m365quotas.colostate.edu/.
This site contains a link to the CSU Source article regarding this change, ways to view your quota and best practices for managing your data and email.
Please keep in mind that WSCOE provides on prem data storage as well, more information can be found here: https://www.engr.colostate.edu/ets/network-folders-and-network-drives/
This space is backed up, unlike OneDrive space.