Trying to use eki-net.com to reserve a seat

Hello,

I am trying to use eki-net.com to reserve a seat with JR pass, however, it doesn't allow me to book the green-car.
Also, the Japanese booking info is different from the English one, for example, sometimes I can see an available seat from the Japanese eki-net.com, but I could see it on eki-net.com/en....

Is this a question somebody can help here?

Thanks in advance,
Mark.