Huh ! That ' s bizarre . Maybe they just got it working ? <| sep |> There are two reasons for this . One was already mentioned by uSherilys , that one is not really a bug , the other guys simply don ' t have the capacity for your mineralsenergy . The other reason is definitely a bug , it happens if you want to trade more than half of your total energy or mineral amount . When you make a trade , the game will deduct the minerals from your pool , and THEN it will check if you even have the minerals for that trade . And this is beyond stupid . Let ' s say you have 5000 minerals , you want to give 3000 to someone . The game deducts the 3000 , THEN it checks if you even have the 3000 . Which , of course , you don ' t have now , you now only have 2000 left in your pool , and it will cancel the trade because of that . It ' s as if you take money out of your wallet , are ready to pay someone , then the game shows up and says But there ' s not enough money in your wallet Yes of course , because it ' s right here , in my hand . Yeah nope , sorry , trade DENIED .