One of my most important work tools is an Office365 SharePoint calendar that I share with some partners and use to keep track of billing hours on. Normally I initially log the hours in my personal calendar and then drag them over to the SharePoint calendar in Outlook.
When I reformated my system recently and started using Outlook 2013, that stopped working. Any time I would try to connect the SharePoint calendar to my Outlook client, it would seem to succeed, but it would never actually load the calendar, and every time I hit Send/Receive, I would get a “Connection to Server Failed, please try again later.”
I called MicrosoftOnline support and had a solution within minutes. Turns out the solution to this issue is merely to go to your Internet Explorer’s Internet Options, go to the Advanced tab, scroll to the bottom and select the TLS 1.0 checkbox.
Once you’ve done that, hitting Send/Receive actually successfully syncs the SharePoint calendar with Outlook. The tech I was working with said that this fix is fairly common with any authentication issue related to an Office App that needs to connect to the SharePoint Online cloud to read/write data.
So it’s may not be exactly an Outlook 2013 bug, it may actually be an issue with IE 10 and SharePoint Online.