: The error might arise from improper integration of the NetSDK into the client application. This could be due to outdated SDK versions, incorrect API calls, or misconfigured parameters.

This error generally occurs when the SmartPSS software attempts to communicate with the recorder (DVR/NVR) or camera to request a video file stream, but the request is rejected or interrupted. While the error sounds technical ("NetSDK"), it is usually caused by simple configuration or network issues.

Start with rebooting the NVR and checking the system time. Nine times out of ten, that will restore your playback. If not, work through the hardware and firmware steps above.