Quicken is so awful in many respects and somewhat competent in others, but I have used it for years and have a lot "invested" in the product.
Recently it stopped connecting to Bank of America and I got it to reconnect by basically disconnecting it from "OneStep Update" and then adding it back. Here's my suggestions:
1. Select your Bank of America account from the navigation pane on the left side.
2. Click on the "Account Actions" dropdown list on the upper right side.
3. Select "Edit Account Details".
4. Select the "Online Services" tab.
5. Select the "Remove from One Step Update" button.
6. Then add the account back by selecting "Activate One Step Update".
7. Bank of America will give you a challenge question.
8. My account then successfully could connect again to Bank of America.