Problem with variables

Hello everyone, 

Unfortunately, I have problems with the variables set in an eLearning project (Storyline 360). They do not work - it is like this:

There are 2 buttons in pink on the main slide. 
The user should click on one button, then a layer appears. When the button is clicked again, the layer disappears. Once the user has started the layer, the associated variable changes from false to true . 

It is the same with the second button.

 If both buttons are clicked and the respective layer is displayed, the two variables change from false to true. 
If both variables are true, the next button should appear. This is hidden at the beginning; the next button should change its state from “Hidden” to “Normal” if both variables have the status “true”. 
Unfortunately, this does not work. 
I have uploaded the slide for you and would be very grateful for any tips. 

BR Steffi