rrondinella - two things to check.
1. Did you adjust your display output resolution on the NVR to 4K (3840x2160)
2. yes - your bitrate is very low - it is at 2 MP value. Try bumping it up to 4096 first (that is still a little low)
The starting value should actually be around 8192 for an 8MP camera - but if you set it that high - also set the Bit Rate Type to VBR insted of CBR. (Variable bit rate instead of constant) That will allow the camera to send smaller bitstream when it can.
Let us know if that helps.