Limitless Pixelmon

its been two years now sense i don't play this cool server the thing is i really want to go back and play this game....
But how? when i join, it says Try to Restart Your game. How can i Fix that guys pls Help me

restart your game.

another problem when install the mod it crashes, or the mod install my computers hang

Gonna need more info than that. Maybe the actual error.

Try adding more ram, I had a simular issue when trying to login about a good few months ago, you can do this by going into your profile settings, which to get to if you have the updated launcher you click on the three lines and go to launch options in there you should see a tab called JVM Arguments click it so its green and you can edit your -Xmx1G- instead of 1 you want to have 2 or 3 i recomend 2. If this doesnt work then i dont know what to do to help.