I am using Outlook 2013. As of about two weeks ago I cannot access my sent mail or my deleted mail. It there a way to get these functions back?

I got this message: Sync Issues (this computer...70
10:48:18 Synchronizer Version 15.0.4971.1000
10:48:18 Synchronizing Mailbox 'tvhagerty@gmail.com'
10:48:19 Synchronizing server changes in folder 'Drafts'
10:48:19 Synchronizing server changes in folder 'Inbox'
10:48:19 Synchronizing server changes in folder '[Gmail]'
10:48:19 Synchronizing server changes in folder 'Important'
10:48:19 Synchronizing server changes in folder 'Starred'
10:48:20 Synchronizing server changes in folder 'Contacts'
10:48:20 Synchronizing server changes in folder 'Important Stuff'
10:48:21 Synchronizing server changes in folder 'Sent Mail'
10:48:21 Error synchronizing folder
10:48:21 [800CCC0F-0-0-560]
10:48:21 Canceled

I don't know what all this means.