[CLIENT] An Unknown Error Has Occurred, Champion Select

This has been really bad lately, during champion select the client will freeze frequently when I try to select a champion. The "Retrieving Data From Server" box pops up and sits there forever until I get the Unknown Error box, sometimes three times in a row. This has caused me to drop out of matches and receive penalties. It also lags up when I try to select runes, sometimes never changing my rune page. Please help fix this!