Google quicken CC-501 and you'll find several threads related to this. If you don't find a solution, try google groups.
Here's an answer from the Quicken site:
What if I get a CC-501 error when using online services?
Answer
Quicken encountered an error while updating your accounts as the result of an error on the Quicken server. All server errors are automatically reported to Intuit for resolution.
There is no action you can take to resolve this error. If you need to update your accounts immediately, you can use an alternative update method. You should use this procedure until the server error is corrected.
Log in to your financial institution's Web site.
Navigate to the download page and click download to Quicken.
Follow the on-screen prompts to update your accounts.
Periodically use the Update Now button on the account Overview or Summary tab to see if the server issue is resolved. Once you successfully update, you can continue using One Step Update for this account.
Notes
Your financial institution cannot resolve this issue. If you need assistance, contact Quicken Help & Support.
