I struggled with how to title this post because readers may not know that you have this issue (and if they do, how do you search for the issue?)
On the My Site profile page just below the default profile information there is a web part that displays the users availability from Exchange.
This web part connects to the Exchange Auto Discover Service to get the information. If the connection fails the whole web part vanishes. You may notice it for just a moment and then it disappears while the page is loading.
While our IT team was upgrading our LCS to OCS they discovered that you need to run the SESTSPN command to map a SPN record to the Client Access Server (in our case it’s one of our Exchange Servers) to the FQDN used by “Exchange Web Services” in our case webmail.catapultsystems.com. This is the command:
The syntax is: setspn -A HTTP/webmail.mycompany.com clientaccessserver