This setting often fixes Email Service Account issues such as, folders or sub-folders not showing (missing) in Outlook Desktop, but showing (not missing) in Outlook on the Web.
Open Outlook Desktop version, click File - Account Settings - Account Settings... (again).
In the E-mail tab, double click on your email address listing.
In the Exchange Account Settings window, click the More Settings... button.
In the Microsoft Exchange window, select the Advanced tab.
In the Advanced tab, uncheck the box next to Download shared folders, then click OK.
Click OK again, then Next, and Finish.Close out of all Outlook windows, then re-open Outlook desktop.The setting should be enabled now.Confirm that desired folders are now showing properly, in Outlook Desktop.