HELP! "There was an error sending your trade offer. Please try again later. (20)"

[Agent Orange]

is it only me or is all player/trader experiencing this :
- when i send steam trade offer this error shows up "There was an error sending your trade offer. Please try again later. (20)"....
- and in a live trade, i cant drag or move my items in the trading panel(right side of the trade window).
can someone help me? plssss