Our survey form will not accept birth date number

I am trying to enter a participants birth date- per the encoded formate and the system will not accept/keeps telling me it is invalid.

I'm sorry, but I cannot find a date field in your list of forms. Please let us know the correct form in question, and we'll check and troubleshoot this for you. 

Our intake form. It is the only one we ever use.

I have re-saved the date picket and cleared the forms cache. Hopefully, that did it. Please update this thread if the issue persists.

Please use the picker instead of typing the date manually to make sure it is validated properly.