Yes, very strange!
Change ch0 to ch1 or ch2 if that makes any difference:
rtsp://admin:xxxxxx@192.168.1.155:554/live/ch1
rtsp://admin:xxxxx@192.168.1.155:554/live/ch2
We have been thru this before and you made it work Netcam software issues and RTSP connection issues with Wansview 720p K2 - #6 by sesipod