Online matches quoting instantly

I play several matches with no lags (ping is good, game runs well) and all of sudden, quits to main menu saying I’ve lost connection. Connects instantly again without delay. I’ve run the connection report and it says good. Why does this keep happening, so frustrating ah! Few days ago, I couldn’t connect to online at all but my internet worked fine. There’s something up with the game/servers, fix it.