2005 Questions for all other cars gas tank clogged?

Unable to fill the gas tank on my 2005 Kia Optima. Clicks off and spills over after less than a second of fueling. It almost as if there's an obstruction, although the gas cap locks and there was no signs of tampering. Was able to get about 1/4 of a tank of gas in after repeated tries spanning over 20 minutes. What might be causing this?