Sent or Deleted after sent order error is what we also call a timeout order. It means that we have properly sent the order to the broker, but we have never received any answer (executed or rejected). It means that we do not have any clue if the trade exists or not. In that case, you should look in your broker terminal to see if the order exists or not.
If it exists, there is a big chance that the Trade Copier does not recognize it and that the trade won't be closed when the Master trade is closed. This error could also mean that the symbol is not tradable or that you have connected your Slave account with the investor password instead of the trader password.
Please double-check if you use the correct password to connect your Slave account.