@RTSP 

Hi,

Currently, the Tapo cameras support up to 4 simultaneous video streams (two mainstreams with high video quality & two substreams with low video quality), and if the camera has subscribed to the Tapo Care service, it will occupy a mainstream.
If you can set up the RTSP connection successfully via the link "rtsp://IP Address/stream2"(substream) but not via the link "rtsp://IP Address/stream1"(mainstream), it may be other devices are streaming the camera via the mainstream. 
To stream the camera via the mainstream, you can reboot the camera, ensure no other devices stream the camera, and try to establish the RTSP mainstream connection.

Best Regards