Are you “the IT person” for your organization? Do you find your users complaining from time to time that the user experience for Office 365 doesn’t work the way that they anticipate that it should? Do they talk about timeouts or error messages popping up stating a component can be loaded?
Have you checked your firewalls to see if you’re actually allowing users to access the SharePoint system? Consider an update sometime soon… follow Microsoft’s guidance and set up your environment appropriately.
Microsoft keeps this document up to date on a regular basis so perhaps setup a reminder using Wunderlist to ensure that you’ve got the latest and greatest information loaded into your firewall.