“Select files” button not working

Hello, I’ve set up a new WordPress website, tried to add my first post and discovered that the “Select files” button doesn’t work while trying to add new media to post/page.

It does work in Media Library, the problem occurs only on post/page edit.

I’ve already tried disabling all the plugins, changed to default theme, checked in Chrome, Firefox and Safari on different computers.

There are no js errors in console, the button just seems to do nothing at all.

Anyone encountered similar issue?