CNET reports that Grand Theft Auto Online, the biggest entertainment release of the year with more than $1 billion in annual sales, is having some trouble getting the gamers online. The title, which launched on game consoles Tuesday morning, is experiencing server issues that have locked out some gamers and made it difficult for those who have gotten in to play the game. Fifteen million people purchased the game when it was released last week — and any number of them could play online when that 'perk' becomes available on October 1. 'At a conservative estimate I would expect about two million players to log on to GTA Online within the first 24 hours,' says Keza MacDonald, UK games editor for IGN.com, the video game and entertainment site. 'Rockstar has never done an online game of this scale before, so they are totally unproven in terms of their network infrastructure.' Rockstar, the game's creator, said that it was doing all it could to buy and access servers to accommodate what was expected to be massive demand for its online title. Meanwhile Twitter is abuzz with complaints from gamers who say they can't get into the service.