Invalid stop loss or take profit
Invalid stop loss or take profit is an error in MT4 that appears when traders set stop loss or take profit values too close to the current market price or in the wrong place. The price distance between stop loss and current price or take profit, and current price needs to be properly set. Sometimes traders put stop loss or target values outside the correct parameters range for that particular instrument.
Case 1:
Traders put stop loss above the current price for BUY trade.
or
Traders put targets below the current price for BUY trade.
This was an example of when a trader made a mistake, but the price’s the wrong value.
Case 2:
Traders put a stop loss below the current price for BUY trade only 2 pips below.
or
Traders put target above the current price for BUY trade only 2 pips above.
This is an example of Invalid Stop Loss or Take Profit because the price value was too close to the current market price.
Of course, always check are there any off quotes MT4 error during the trading and that you have an excellent internet connection.