Question: What does 'Invalid S/L or T/P' error message mean on MT4/MT5 platforms?
The “Invalid S/L or T/P” error message appears if the stop loss or take profit you’re trying to place is not within the correct parameters of the limit and stop levels for that particular instrument.
Most of the cases, you just need to switch the price of Stop Loss and Take Profit, and the order can be placed.
For example, if you want to place a buy(long) order, then the Take Profit price should be above the price and the Stop Loss price should be below the price. And vise versa.
MetaTrader will also show you with error message immediately when you set wrong parameters of the order.
If the concept is too complicated, you can also just order a position without S/L and T/P, then set these parameters by dragging the line in the price chart.
MetaTrader has got several different ways to place orders.
FAQ – How to show ‘New Order’ window on MT4/MT5 trading platforms?