Here's a quick tip. We've recently had several clients update their QuickBooks installations to the 2015 version. Inexplicably, the WebConnector app that allows them to download details from WooCommerce stopped working and reported an invalid password problem. Changing the password in WebConnector and the QuickBooks WooCommerce plugin did nothing to alleviate the problem. What worked was to change the userid in the QuickBooks WooCommerce extension and reinitialize the WebConnector app.