Seems like we all are having the same error/issue. No one so far has given an answer to this. So i urge you all to send a complaint directly to the respective email address . However, i suspect that there is a problem in the website (a bug). Have you guys tried "Forgot Confirmation Number" link? that too doesn't work, especially if you set the current year. Pretty convinced its a bug which has been there for a week or so. Else, lets all check again after a week or so.
Kentucky Consular Center (KCC) - KCCDV@state.gov
Email: KCCDV@state.gov You must include your name, birthdate and case number exactly as they appear in the Entrant Status Check (ESC) website. Ref: https://travel.state.gov/content/travel/en/contact-us/us-visas.html#:~:text=Kentucky%20Consular%20Center%20(KCC),Status%20Check%20(ESC)%20website.