Why is flexbox not working in IE?

Question

css

Prefixes are written like this

display: -webkit-box;
        display: -ms-flexbox;
        display: flex;
        -webkit-box-pack: center;
            -ms-flex-pack: center;
                justify-content: center;
        -webkit-box-align: center;
            -ms-flex-align: center;
                align-items: center;

Answer 1

Looking in what version?
Have a look at each property at https://caniuse.com
Something tells me they are not supported by your donkey version

Answer 2

flex works adequately starting only with the 10th version of IE. In the 9th it also works, but some properties are not displayed correctly.