Claim Contains Invalid Diagnosis Code References in Line Items (RC66)

One of the line items does not?a valid letter?for the diagnosis code pointer in box 24e on the inbound file.

Verify all of the diagnosis code values in box 24e and update the claim as necessary. ** This box can contain ONLY letters, no special characters. If more than 1 letter will be used, send next to each other, ex: AB (referring to diagnosis codes?A and B)