images – Pictures randomly replaced by blue question mark

My pictures are sometime replaced by blue question mark

On the devices that have already visited my website, some pictures are randomly replaced by blue question mark. (first time visitors usually don’t have this issue).
I talked to the hosting support and I deactivated and purged cache from everywhere but still have the issue.

Hosting company is suggesting maybe a theme cach or so. Do you have any idea? Here is a screenshot of my website from a device that already visited it before :

I’m running lated wordpress version with Chaplin theme (up to date as well).

And it looks like it happens more on Safari. On my iPhone all pictures are fine except the logo, I can’t figure it out.