The blank on Credit Card field should be when you test it on with pinpad.
![image](https://s3.amazonaws.com/cdn.freshdesk.com/data/helpdesk/attachments/production/66056518127/original/IzsjOBzMpVwAHaKU4ftG6nq6acW7miM1WQ.png?1687551764)
The Invalid Field - Auth Amount should be when you test it on without pinpad.
Note: This is a just workaround. Developer is working on the fix.
The workaround it to preauth on the original invoice the the amount, rather than collect card for 0 amount.