Server disconnection and quick play bans

My internet is completely fine, and I'm on a steady 20 ping at pretty much all times in the game.

However, sometimes a red connection error symbol appears on the left of my screen while everything is still going on and I have no internet issues whatsoever.

I then get disconnected from the server and receive bans. This is not an issue with my internet, and I find it stupid that blizzard is killing their own game like this.