Yes, trade context is a well known error.
Means you've sent a trade, and before you received a reply you've sent another. Can be because you're running more than 1 EA that's trying to trade at the same time or you've sent a trade but the server is hanging and not getting back to you before you send the next one.
To resolve it if you're using more than 1 EA, set a global variable that all the EA's must read before it trades. So if EA 1 is about to trade, set the variable to 1 or something, do the trade and then reset it to 0. So if EA 2 gets there and it's already 1, make it wait till it is 0, then send your trade.