Some users have encountered issues getting into their email because they are using the incorrect email application. Your PCs (manager/corporate PCs) have two separate email applications installed on them, Mail and Outlook.
The Outlook app is the one you're going to want to use, the programs can be easily identified by their app icon:
Mail: 
Outlook:
If you don't see the icon for Outlook on your desktop, you can search for it using the search function within Windows:
- Next to your Start button, in the bottom left corner, you should see either a search bar or a magnifying glass:
- Clicking either of these will allow you to search for an app. Type Outlook into the search. Open Outlook by clicking the icon on the left pane or the Open option on the right:
- Once you have Outlook open you can pin it to you taskbar so it doesn't get lost by right clicking the icon on the taskbar and selecting "Pin to taskbar":
- The Mail app may be pinned by default, you can remove it by right clicking that icon on your taskbar and selecting "Unpin from taskbar". This will remove the unwanted app from your desktop so you don't open it accidentally going forward.