The payer is rejecting stating that the date of birth you have provided for the patient (client) is not valid. They are specifically pointing to the year that you have entered.
You will want to open the edit client form for this patient in Therabill and check the birthdate that you have entered. Make sure it is the same birthdate that the payer has on file for the patient.
IMPORTANT: It is also a good idea to check the insurance card that you have entered in Therabill, especially if the insured is the patient.