I own an old Stem Innovation iZon camera which works fine with VLC reading the rtsp stream.
When attempting to connect to angelcam it somehow succeeds (stream seems to be detected) but it then gives an error when trying to play the stream.
please feel free to send me a request through our messenger or to our support email and include the URL as well. I’ll try checking the RTSP stream to see why it isn’t working. This appears to be some specific compatibility issue.