»[Can't connect to server] help pls.

Basically my friend can't connect to server. It started 2 days ago, January 14. Actually everything is fine on Friday he still can play but the next day "Can't connect to server." popped. Not only on Guildcraft but on every server that he added. First i said to him maybe it's his internet connection but he said that his connection is fine he could watch youtube and do stuffs but he cant connect to Guildcraft all of a sudden. I cant really help him that much because all i can think of is his internet connection, so can any one pls. help him. thanks.

Heres a picture.

 

Firewall?

 

@StarAronjay are you still having troubles?