Prediction does not work

I’m just beginning to learn the prediction model in the intelligence feature. I make a very simple example of predicting quantity orders depending of the clients A, B, C. I need some help because it does not predict the values, I don’t know if I’m doing something wrong.

  1. First I train the model with the training data:
    Captura de Pantalla 2021-02-07 a la(s) 4.31.44 p. m.

  2. I copied the formula and pasted it in the initial value of the column “Cantidad”. Also i select the option of make a virtual column with the prediction output.

  3. When I try to make a new record, I select the Client, but the prediction does not appear.
    Captura de Pantalla 2021-02-07 a la(s) 4.25.58 p. m.

I greatly appreciate your help in this topic.