1. This issue may caused by the I/O shield installation improperly or the thickness of the I/O shield
2. You may need to push your motherboard harder toward the I/O shield
3. This tip is quite common when assemblying the PC (same when installing the CPU cooler)
*Please note: Do not screw all the way in at first, please screw in the holes little by little. ex.1>2>3>4>1>2>3>4