Errors in the past days I have had:

Error #1:

- I log onto the game client
- I click "Play" then "Ranked" then "Solo" then "5v5"
- Error: "Cannot connect to PvP.Net Client"

Error #2:

- I log onto game client
- I click "Play" then "Ranked" then "Solo" then "5v5"
- I proceed as normal until the countdown finishes
- The game never starts. I have to quit the game, log in again, and rejoin the game.

I've had these happen a lot too. It happens sometimes when I:

try to save masteries
try to select a hero
Try to join practice games
As well as Error #1 & 2, but I get those for normal games because I don't play ranked

They don't happen every time I try to do one of those things, but they happen way too frequently, and its getting annoying.