That is the Bank selection field - go further down the screen
When receiving a payment against an Invoice you don’t select anything under “Item”.
Click on the “x” in the Item field to clear the line.
Now, under the Accounts field select “Accounts Receivable” + :Customer + invoice as shown above
In fact, when you “click on RECEIVE MONEY in the VIEW INVOICE” and after selecting the bank that line should be automatically completed as required.
So why don’t you delete the current receipt and start again from RECEIVE MONEY in the VIEW INVOICE