Microsoft Office 2007 has reached its "end of support" date.
Unusually for Microsoft, if you're still using Outlook 2007 to connect to Office 365 for your email, calendar and contacts, it will stop working - you can no longer access your Office 365 mailbox with Outlook 2007.
What is end of support?
After it's "end of support" date, there will be no more feature or security updates released for Microsoft Office 2007 products (Access, Excel, Outlook, Powerpoint or Word 2007).
By not upgrading to a modern version of Microsoft Office, you will be exposing your computer to an increasing risk of infection by malware and other form of cyber attack as vulnerabilities in later versions of Office products are reverse engineered by attackers.
In this case, Microsoft have also switched off the technologies within Office 365 that allow Outlook 2007 to communicate with your Office 365 mailbox.
Why is this happenning?
Microsoft Office 2007 is now ten years old, and there have been three major subsequent releases since then - Office 2010, 2013 and the current version, Office 2016.
Microsoft, like other software companies, need to focus their resources on developing the current versions of their products, and as such, cannot support older versions of their products indefinitely.
What should you do next?
If you use Microsoft Office 365 for email / calendar / contacts, we recommend that you upgrade to one of the Office 365 plans for enterprise or small business users which includes the latest version of the Office applications:
This will also enable you to use modern security features such as Two Factor Authentication, which we recommend using wherever it is available to improve the security of your online services.
If you don't use Office 365, we recommend you consider upgrading to the Microsoft Office 2016 via volume licensing.