I think it’s a combination of many of the things mentioned. In your router try either increasing or decreasing (some one who knows more about this can contribute) the number of “sessions” allowed.

Also reducing your download speed in steam (I have it at 768k where it was at 10mb by default and I’m on very slow net).

Also if you don’t already put limits on what your browser searches for cutting out all empty/pw protected/above xxx ping etc).

Wait for while between refreshing the list and mainly use your favourites or history. The stv tab in game is busted though :(.