Some cameras stream data in a different way. Usually 2 protocols are used for streaming: UDP (faster, but less reliable) and TCP (more reliable, but slower). Nx Witness  tries to determine the best protocol for the camera. However, sometimes camera may  have issues when streaming via the chosen protocol.  In this case setting the protocol manually may help.

To do so:

1.Open Camera Settings and go to Expert.

2.Check I have read the manual and understand the risks.

3.Choose RTP Transport and click OK or Apply.

4.Restart the camera.

5.If the changes do not help, choose a different protocol and restart once more.