Buffalo

Me and my friends recently tried to run a modded forge server because our old way of playing together (essential mod) was way too laggy for us and figured it would be way nicer if we just had a dedicated server running from one of our PC's I finished everything up and was finally about to start the server then the command prompt randomly stops, I am completely new to server hosting and dont understand what I did wrong. I watched the same tutorial video atleast 6 times and this is the only issue that appears. These links are pictures of the command prompt crash: https://gyazo.com/b52b07d3d8ffb61d271dc01d7006a5f3 https://gyazo.com/22ece813f0302cfd0cb023e09680b432 (When i press any key it just closes the command prompt))