sutting down eternal server help

my Friend was trying to start a server and he did but when he tried to play it says shutting down internal server he is using technic laucher and playing the 1.7.10 pack he cant even play singel player (im sorry if my english is bad)

the pc is not bad it can run battelfield V all ultra at 60 fps its good and i think the problem its with the network i dont know we are trying to play a modded server i can enter but he cant

thats the error

can some one help

its the same mesage for single player and multiplayer