SQL Server 2012 :: Daily Maximum Sold - Per Day

I have a code I wrote and I'm required to get Product Name and Quantity with the maximum quantity sold per day. My issue is with the "per day" part, here's my code below.

SELECT
t.SalesOrder
,t.OrderQuantity
,t.OrderTotal
,t.OrderDate
,p.ProductName

FROM Transactions t
INNER JOIN SalesPerson sp
ON t.SalesPersonID = sp.SalesPersonID
INNER JOIN Product p
ON t.ProductID = p.ProductID

WHERE sp.SalesPersonName LIKE 'John%'

Now from this code I need to get only Product Name and Quantity with the maximum quantity sold per day, here's what I tried;

SELECT
SUM(t.OrderQuantity) AS Order_Quantity
,p.ProductName

FROM Transactions t
INNER JOIN Product p
ON t.ProductID = p.ProductID

WHERE sp.SalesPersonName LIKE 'John%'
GROUP BY p.ProductName, t.OrderQuantity
HAVING MAX(t.OrderQuantity)