Odd as it may sound it is not unheard of to have a "new" battery and/or alternator to be defective, so these should be checked. Also recheck all wires and cables involved to be sure they are connected tightly and properly. Not sure if your OBD port will send data if engine isn't running but could be worth a try. Also, hit the starter with a hammer a few times. Seriously. If you have a solenoid on the starter it should be double checked. Previous answer is best place to start.