I didn't notice this until the other day when I tried to play Worms: Battle Islands online...
Apparently, the Worms franchise has had their games' online be supported by GameSpy. However, if you aren't aware, GameSpy shut down on May 31st, 2014. This caused all games that used GameSpy as their online multiplayer client to close their online, including the Worms franchise (assuming that all other Worms games besides Battle Islands use GameSpy as their online client).
Sorry, guys.. :/