13w39b multiplayer crash

i am running a minecraft server for myself and some friends, and i am getting sent back to the log in screen after i enter my server. (what i mean is i get onto the server, then after about 1 to 5 seconds, it varies, the i am sent back to the log in screen) i am currently an op on the server, and have tried playing in both creative and survival, as well as both as and as not an op. regardless of which settings im using i still get set back, and the problem seems to only effect me as the server runner, as my friends are still able to play without any problems