Category: Acknowledgement/Returned as unprocessable claim

We keep getting rejects with the following wording, wondering what others have done because it seems to stop them from ever getting to the payer, but doesnt really say whats wrong?

 Category: Acknowledgement/Returned as unprocessable claim  The Cl
aim/Encounter has been rejected and has not been entered into the adjudication system St
atus: Processed according to contract provisions (Contract refers to provisions that exi
st between the Health Plan and a Provider of Health Care Services)