Huge irregular lags

Hi, sometimes (about 5% of time) i get 1-4 minutes lag. This lag is on chat, joining the game, ending turn, everywhere. When i have this lag and i do not click "end turn" button then turn always fail. Nothing happening and i am show as someone inactive at last turn. For example when i have 2 min. lag then turn fail if i click "end turn" less then 2 min. before turn ends automatically and success only if i click it more then 2 min. before turn ends automatically. When this is happening my Internet transfer is at the same low level when atwar works fine. When this is happening speed of my connection can get at the same maximum level as always, when i am f.e. turning on youtube to check the speed.
What can I do to fix it?
Sorry for my bad English.