Unable to spectate games on the main section of the launcher

I am unsure when this started to happen, but it seems it has started after the last update. I am no longer able to spectate any game. Eveny my friends'!

I didn't modify anything in the game files nor my internet connection have problem. I had no problem spectating games before. I even re-installed the game and nothing changed.

I also sometimes see error window when I ALT + TAB out of the game that states something like "UNABLE TO CONNECT TO SPECTATE GAME". I only see this when I ALT + TAB out. Sometimes when I wait, I can enter the spectating game but all characters aren't in motion. I mean the game doesn't freeze; I can still see the "standing animations". Its just that they're not doing anything.

I've checked numerous past posts but none of them had any solution.

Please help me.