Go to setup Customize Users 'Page Layout' Edit the Page Layout. Under the Page Layout drag the fields and buttons specified below to add it in Page Layout and Save. Enter the values to these fields as mentioned below.
Field "DBSync Id" ? DBSync User Id must be entered
Field "DBSync Passwd" ? DBSync Password must be entered
Field "DBSync Server URL" ? URL must be "https://dbsync01.appmashups.com/qboev3"
Field "DBSync Profile" ? Profile Name must be "SalesforceQuickBooksOnlineBiDirectional"