If your bank recently required you to reauthorize your checking account and/or your bank has changed from "Direct Connect" to either "Express Web Connect" or "Express Web Connect+" you can no longer use Online Bill Pay direct to the bank or Quicken Bill Manager's Quick Pay function. The bank no longer supports this function through Quicken.
You have these alternatives:
I've been using a variation of method #3 for decades, since before the Internet and dial-up were even invented. It's easy to get used to this process. And I have yet to miss a single payment.