Auto-code, by default, is not enabled upon opening Customer/Supplier Maintenance form. To enable it, Customer/Supplier name must be filled in first then the Auto-Code will now be clickable. In some instances, after filling in Customer/Supplier Name field, Auto-Code button is still disabled.
Go to File > General Maintenance > Default Interface Account
Check the Debtor/Creditor Control Account
For Debtor Control Account, set it to ACCOUNTS RECEIVABLE – TRADE. For Creditor Control Account, set it to ACCOUNTS PAYABLE – TRADE. Click Save.
Go back to Customer/Supplier Maintenance form. Notice that after filling in Customer Name, Auto Code is now clickable.