Thank you for advice! The problem was with one of the plugins.

Now I have another inconvenience. Images have different sizes and I’ve got these grey gaps:

What should I do for solving this problem? I want the system automaticly optimize sizes picking them from articles and resizing for grids.

And why is it impossible to change the order of articles in grids manually? There are so many options like “latest”, “oldest”, and “a-z” but there is no simple opportunity to make it by myself.