Hello @Jay Berman,
Thank you for reaching out to the Quicken Community, though I do apologize that you are experiencing this issue.
This can happen if you have deactivated or deleted an account and then restored a Quicken backup file. You may follow this link to access a FAQ that provides some troubleshooting steps to take when presented with a CC-800 error message. It is recommended to save a backup before proceeding (just in case).
I hope this helps!