User ID and PIN for Direct Connect should be readily available from your bank. They are typically different from logins for website access. Some banks do charge for direct connect services.
When you setup your online banking, select the account from the sidebar, go to Setup Online Banking and the important step ( in the documentation) is to select "NEW CONNECTION", even if your previous selection is already on the pick list. That will reset previous settings/entries.
PS Sorry, I re-read your OP and realize that you have DC already setup. I would just tell them that you were setting up your financial software again and you need the credentials. They will certainly be able to verify your identity and there should be a knowledgeable person on the other end from "Quicken" support to give you the information.
Just as an aside, I had told my Credit Union that I was using Moneydance and they didn't care, they just had never heard of it. I have read that other banks tell the customer that "they only support Quicken".