iViewer installation and user guide
When I playback the recording file on the iViewer, it can not show the video. But, if I playback the video on the IE browser, it is workable.
Answer
iViewer gets current time from phone to play videos. When you open NVR web UI, NVR will show the time according to customer setup and play videos according to the time. If NVR time sets to 2018 and the time of mobile phone is 2019, iViewer will not find videos in 2019 but find videos in 2018 when iViewer plays NVR recorded videos.