Pagination of "blog posts" doesn't work

Hi,

on our homepage (https://www.mines-telecom.fr), the pagination of the “blog posts” content element (title : “A la une”) doesn’t work anymore. The same post is displayed whatever page you click on…

The content element parameters are : display posts, category ‘a la une’ (a category that exists of course), grid model, 1 column, with pagination.

Could you help us ?

Thanks.
Oli