It has come to our attention that anyone using QuickBooks2013 must update to the most current version of QuickBooks to continue using the Web Connector. Those who do not update will most likely experience issues while syncing.
Our support team has resolved several cases by instructing the caller to update their QuickBooks. In most cases closing and re-opening QuickBooks will cause it to check to make sure it’s running the latest version. You can update the version you are on by going to Help > Update QuickBooks
For any additional details regarding QuickBooks 2013 check out the intuit support site or call their support line for help.