Offline mode enables you to use many of the core features of an application, even when you don't have access to the Internet. If you're working in Offline mode in Outlook 2013 or Office 365 and want to switch back to Online mode, you can do so via the Send/Receive group. Visit the Tips section if you're just looking for information on how to join a network on your Windows 8 computer.
Click the "Send/Receive" group to reveal the Work Offline button.
Verify that the Work Offline button is blue. If it isn't, you are already online and any connectivity issues you are having are unrelated to Microsoft Outlook or Office 365. See the Tips section for advice on how to troubleshoot your Internet connection.
Click the "Work Offline" button to go online. You will know Outlook and Office 365 are in Online mode when the Work Offline button is white. The Working Offline icon will also disappear from the status bar at the bottom of your screen.