Same problem FDP-106 with HSA Bank. They've changed their website, or at least the log-in website. Initially it was hsabank.com, then it takes you account.hsabank.com, which is a useless page, with a button that says "View Account." When you click on it, it FINALLY takes you to your account info. I suspect this is what's tripping up the Quicken connection.
Account not found. No accounts returned - case 106
then again, HSA Bank mentioned above lets me log-in and sends me a six-digit code, THEN after that is when it fails. This is for a Mac.
You are likely experiencing error FDP-106 due to changes you mentioned that have been made at the bank's website.
If you haven't already, please take a moment to review and follow the error-specific troubleshooting instructions found in this support article.
I hope this helps!