Cannot see IP cams online...

Hi, i'm Calvin, new here.
I have a problem with my NVR (7616ni-i2/16p): when i connect my cams (2142 and 2432) to lan ports of the NVR, i can see cams no more... just NVR can see them, but not online, not with SADP...

Otherwise if i connect cams to my switch i can see them again (NVR, Online, Sadp)....

So i have to do something to my NVR to open lan ports maybe?

Thanks !