Vanilla Server - Players get Disconnected: "Take too long to log in"

Ever since trying out the newest snapsoht, the console is spitting out the error contained in the file "error.txt" (attached) after rejecting to connect a player because they "took too long to log in"

I checked my internet connection, router, port mapping, and redownloaded the .jar, so i know that none of those are the problem. I can connect to the server fine using "localhost"