No sidebars on first visits

Hello,
I installed Alium theme on my website.
All is ok but I saw a problem.

All for me was ok but some new visitors can't see and access to my 2 sidebars (left and right)
There is only the central block.

I tried on another browser and I obtained it too!
After many refresh, My sidebars appear.

Did you know this problem?

How can I do to make my sidebars appear on the first visit and always for everybody?

thank you

PS: I don't know if I can but I may give my url to see

Screenshot

and screenshot on a new browser for a 1st visit

my website url to see : http://www.alloprono.fr

thank you

As I can see there are two sidebars but one of them - the left one - is empty. You have to add widgets to it on page Appearance --> Widgets.

Yes
I made many tests and I made them empty to see if they are visible.
When i put the widget in, they become invisible.
I put widget in, and you can see now:
no sidebars :( (the same for the footer)

thanks for your answer :)

edit : it works ok (i am so happy ^^)
I disabled an extension : woosidebars which surely might a conflict with my theme!!

thank you