Ceptara/Toodledo/Outlook task folders

I am using Ceptara, Toodledo and Outlook.  I access Toodledo on my iPhone and my PC.  I have assigned folders to my tasks in Toodledo and the task assignments disappear periodically.  The folders still exist, but there aren't any tasks in them and when I look at each task, it says "No Folder".  I suspect it's an issue of syncing through Ceptara.  Any advice?