If not, using the pencil icon, in the popup edit the password to the same exact password as the NVR .
I’ve seen older NVRs take quite a while to register a new camera.
If that doesn’t work you need to open the camera and do a hard reset with the physical button held for 45 secondS. Then wait 30 min again.
Go to the live view and see if your cameras are showing.
If that doesn’t work I don’t know what to tell you.