“If mistakes happen, effective leaders don’t place blame on others. They take ownership of the mistakes, determine what went wrong, develop solutions to correct those mistakes and prevent them from happening again as they move forward.”
One of my favorite principles on leadership is taking ownership for everything. This is even more important when those you lead are failing. They are not failing you are and you are the one with the power to help them succeed. Does that mean they are the right employee? No, but you are still the one in control of them being in that position so either help them with the necessary training or help them find another seat.