Internal exception:''io.netty.handler.timeout.readtimeoutexception''

So,I don't know what to do.In MineCraft i keep getting the same problem!
It is Internal exception:''io.netty.handler.timeout.readtimeoutexception''
I do not know how to fix it and it is based on me logging in... then when i log in theres everything like in the game but there is ground i fall down the world when i look down its black and when i look up its the normal sun and normal sky ect.Thegorund dissapears and everything freezes and i dont know what to do please message me back if you know how you fix....