[Client] Can't spectate Ranked/Normal/Custom games at all

This has been going on for several patches now, where if I try to spectate my friends Ranked or Normal or even Custom games, I get a client error. The screen starts loading and sometimes I see the actual players and their % loaded but most times its a black screen that doesn't even fully cover the computer screen and a notification that there was no connection to the spectator client. This has been happening since November for me. Please help! My friend is trying to teach me and wants me to watch his games to observe other players and their techniques but this hasn't been successful lately.