Hi,
Please check if you can run gst-launch-1.0 command:
$ gst-launch-1.0 uridecodebin uri=rtsp://_RTSP_IP_ADDRESS_ ! nvoverlaysink
If it works in the command, please try the python sample:
Doesn't work nvv4l2decoder for decoding RTSP in gstreamer + opencv - #3 by DaneLLL