Empty page when I want to customize it

When I want to customize the home page, the page is empty.
And when I click on Widgets in the left menu, they don’t appear.
The page is niceroulements.sgarroni.com.
Thank you for your help.

Hello there,

I hope you are doing well today.

Please ensure that you have updated the theme and WordPress, which can be done via Dashboard > Updates. Also, please go to Appearance > About Shapely and install the Shapely Companion Plugin which grants you access to the Shapely widgets.

Best Regards,

Thank you for your message.
All the widgets, plugins … are updated.
The Shapely Companion Plugin is installed.