Work and doesn’t

Hi,
I’m trying it on different sites,
it just doesn’t work on all of them

and on 1 site some articles are ok, but not all of them,
I tryed to refresh permalink, but impossible to see a difference,
when I indicate the page :
site/adresse-of-the-post/amp/
the browser show :
site/adresse-of-the-post/

is there solution or way to find the problem ?
what could be ?

thanks for your help