To check the availability situation, you need to access transaction CO09. As this is a sales order, you need to access CO09 with checking rule "A" (unless it involves special stocks). So you need to access CO09 with the following parameters:
Material : 1000449864
Plant [Your Plant]
Checking Rule: A
In here, check the value in "Cumulative ATP Quantity". I assume it will show that there is no available quantity until 1st July (I suspect that 1st July may have been your end lead date).
After checking CO09, if you cannot understand ATP result, then please post 2 screenshots back here:
1) In schedule line, press shipping button and post screenshot of the dates .
2) Screenshot of CO09.