Regarding this ticket, (Ticket #10793219), I was experiencing the same problems the past few weeks up until yesterday, 2/6, so I used Marcus/Goldman Sach's online text support app asking them for a status. They informed me they never supported the interfacing/downloading of data with Quicken, so I told them I was going to close my accounts because it worked up until last month.
Oddly enough, just for the heck of it, I thought I would try again tonight, and I was able to successfully connect and download my data into Quicken. Not sure how long this will last but wanted to inform everyone.