Ensure that All Dx checkboxes are checked on the Transaction page.
To cause these checkboxes to automatically as new diagnosis codes are added go to System\System Parameters Maintenance\System Settings and click the option to "Check all Diagnosis indicators by default".
Check your HCFA form for the visibility of the data placeholder for the diagnosis codes. Reindex.
If this doesn't work, this will: 1. In Transaction pane, Click Diagnosis 2. Click Update Defaults 3. Click Ok 4. Click Save and Do Billing again.