i tried zoneminder on a Virtual machine linux box, and i configured it weel because it worked.
Now i moved to a real pc with Debian installed (Debian 9).
Everything seems to work except the streaming:
I see this image:

forum image host
So everything seems ok, but when i click on it i see no image. With the same monitor configuration on my Linux VM everything works.
Sorry if this is a simple quesiton but i'm a newbie of ZM and also reading old posts didin't helped me.