Make sure the NVR is on the latest firmware. I believe it’s 3.4.92 for the DS-7608NI-E2. You can download the latest firmware from the same place you got the SADP tool. Please read follow and understand the instructions and warnings on the firmware pages. Main thing to understand is DO NOT skip versions. Default Whatever version it’s on now install that one again and then proceed to install every version until your at the current version. Put the firmware files on a flash drive and plug it into the NVR. Make sure all the cameras are disconnected from the back of the NVR before the upgrade / ‘s
Proceed with upgrade.
At this point the NVR is at its most default settings and you still have all the cameras disconnected.
Check and see if the alarm is there.
If it is, you have a faulty NVR
If it isn’t, the problem lies downstream of the NVR.
Start with the cabling. Make sure your runs of cat5e / cat6 are no more than 300’ using outdoor rated cable where appropriate.