Can't access sites from localhost

Hello,

I found a strange issue on all my Plesk installations...

Since 14 january, 2019, a client tell me PDF generation on his website does not works anymore.
When I look at the code, some images are integrated with full URL (https://example.com/image.jpg) instead path (/var/www/blah/image.jpg), because path do not works (strange too, but the library is very limited, so why not).

If I try to go on https://example.com/image.jpg from my computer, everything is fine,...

Can't access sites from localhost