Sync Error HTTP 400

Each time I try to sync with the Cloud I get this error: Quicken encountered a client side error while syncing your data [HTTP-400]. Try again later, if the error persists contact Quicken support. I've tried all day with no change. My Banking & Credit does appear to be syncing - as well as transactions - but my Property and Debt is not. I have the Home, Business and Rental Property version and do have rental properties (and mortgages) set up. Anyone know what is causing this?