Why doesn't Flex-Box layout work on mobile?

Question

css

I started making adaptive layout for my project whister.websozidatel.ru/. I got to mobile phones, the resolution is about 744 pixels. I tested it on the Samsung Galaxy Grand 2 phone. And it turned out that the flex-box layout is generally ignored by this phone. And looking through the same www.responsinator.com/?url=http%3A%2F%2Fwhister.we... everything is displayed normally.
Why is that? And what can be done in this case?

Answer 1

Need an autoprefixer

Answer 2

You probably have an old android browser.
caniuse.com/#search=flex
Flex is supported by the standard browser starting from android version 4.4