Since I have installed the new client, I have had to instances where I have disconnected with fine internet and I can't get in. This is only on the new client and is annoying because it got in the way of a Xayah game, the only time I could get her, and then before in a ranked game.
Use the Hextech Repair Tool. It is a very fast way to fix your internet connection and makes reinstalling the game (if necessary) much easier. It has fixed many of my issues.
Another issue may be that your cable modem is out of date. That can cause your router to not connect to wifi, giving a false sense of internet.
