Trouble with creating boxplots

Hello everyone!
I want to visually inspect whether I have a similarly shaped distribution in a question having a scale dependent variable and a 3-group categorical (nominal) independent variable.

For that reason, I am trying to create a boxplot on spss v.23 but I am presented with the graph you can see in the picture I have attached.

Do you know why this happens and how I can fix the problem?
Thank you very much for your time!