Black Screen as I entered ARAM{CLIENT}

After a few minutes of having logged on to the client, I queued up to play ARAM. All was usual and normal until I click the accept icon. Once we entered the match My screen was as is depicted above until the game started. I did not close the client do to the fear on penalization but soon after the game began. All is well in the game. But I just wanted to report this black screen incase it had affected anyone else.