Symptom. Clicking Cash on a Cash Sales document shows There is not payment method which have payment type as 'Cash'.
Cause. The Cash button looks for the first payment method whose Payment Type is Cash. If that payment method was deleted, or its type was changed, there is nothing for the button to use.
Fix.
- Open General Maintenance → Payment Method Maintenance.
- Edit your cash payment method and set Payment Type to Cash.
- Save and try the Cash Sales document again.
Tip. If you keep several cash-type methods, only the first one in the list is used by the button. Give the type Cash only to the method you want the button to pick.
Written by Chantch from the vendor documentation. Source: AutoCount wiki