
Microsoft wants to move away from the basic authentication systems used in older versions of Outlook and instead ensure everyone connecting to its Microsoft 365 services use more modern and secure protocols. So why the push to using newer versions of Outlook? Microsoft have stated that it has seen a steadly and constant decline in the use of old Outlooks versions since its initial announcement of the change last year which is a good sign that most customers have already upgraded to newer versions of Outlook.
Note: If Quick Repair does not fix this issue, you can try running the Online Repair as outlined above.Although the 1st November deadline has been publicised for a few months, Microsoft now wants to ensure customers move to a newer version of Outlook in time before the deadline and to prevent any work disruption. After the repair is finished, please restart the PC try the sync again. Select Online Repair and Continue then follow the prompts. (Selection also say Microsoft Office 365). WARNING: An Online Repair does an uninstall then a reinstall of Office, if something goes wrong in this process, you may need to reinstall Office manually which may require a product key Click Install and follow any prompts provided by the repair tool. Select the Reinstall or Repair button, click Next. Open Control Panel (Start>Settings>Control Panel). Click Continue, and then Start Diagnostics. On the Help menu, click Office Diagnostics.
After the repair is finished, please try the sync again.Select Repair, Quick Repair and Continue then follow the prompts.Click Change (may be listed as Modify).(Selection also say Microsoft Office 365 or Microsoft 365). Open up the Control Panel on your PC (and show All Control Panel items, if necessary) and click on Programs, then Programs and Features.