When the Tab key is pressed, the next text input is still hidden so it can’t be focused.
For the Tab key to work, please make all your text inputs appear at the same time.
If you want to prevent the user from clicking/typing into subsequent text inputs, you can use images or shapes to cover them as if they’re hidden, and hide these images/shapes when the previous text input is correct.
Moreover, all text inputs should have Auto or continuous (1, 2, 3…) tab orders. In your first slide, Text Box 83 tab order is 1, but Text Box 91 and 95 tab order is auto so it will not work properly. Please change the Text Box 83 tab order to auto.