I started having this issue a few months ago as well. I am attempting to sync a credit card via Chase to Quickbooks. It was working at one point and now it is not. Quickbooks responds with "The Chase Bank site is down for maintenance" when attempting to sync, although the Chase site is absolutely NOT down, and other apps that I use (YNAB for example) are handling the Chase integrations fine and without fail. As a developer I understand that keeping up with different integrations is hard, but Chase is one of the most popular banks in the U.S. and this integration is critical to many businesses.