Well on my Windows 10x64 PC, FF v52.9 I get the following error in the DNR screen which if I select for details, Jave console shows:
CacheEntry[http://192.168.0.202/dlink/NvrStreamCom.jar]: updateAvailable=false,lastModified=Tue Jan 21 16:44:01 MST 2020,length=-1
Missing Application-Name manifest attribute for: http://192.168.0.202/dlink/NvrStreamCom.jar
NVR Stream Player NVR v2.02.05
Not sure what this means exactly. Java is loaded on this PC.
Native IE11x32 works and shows the video for my two cameras sans my 3rd DCS-936L which I updated to recent FW which breaks the DNR connection with camera. I might downgrade it back to v1.06 which worked last time I believe.
MS Edge works as well using your IE tabs plug in for Edge and Java installed as well.
After downgrading my DCS-936L back to v1.06, the DNR is connecting to it now.