MiniShiiv

I have just recently downloaded Technic Launcher to install mods like Pixelmon, and possibly others as I get comfortable with it. However, whenever I press "Play" on the modpack of choice, it loads, closes, and then reopens. Nothing happens but that. I've tried this with one other modpack, same result. I tried reinstalling the first one, same thing happens. When I go into the server, it says this: https://prntscr.com/obm4hs What am I doing wrong?