@claincly Please could you take a look?

In general a 5xx error signals some sort of server error.

But in order to investigate on our end,please provide a log of RTSP messages.

The easiest way is to use the RtspMediaSource.Factory method setDebugLoggingEnabled()

I'm keen to think the same, that the server is the problem but I wanted to double check, maybe something is missing/done wrong in the ExoPlayer. Or does someone have other rtsp streams to share? Preferably with authentication.

I cannot find the setDebugLoggingEnabled() method if I get the dependency from the Google Maven repository. Should I add it as a module of my app? In that case, what branch should I use?

Also I think for best debugging you can simply try to add "rtsp://demo:demo@ipvmdemo.dyndns.org:5541/onvif-media/media.amp?profile=profile_1_h264&sessiontimeout=60&streamtype=unicast" url to your ExoPlayer sample app and try to play the stream. It should give you the same error. Try a few times as it may be the case it works sometimes :)

I'll try the link thanks!

For future reference, this is how to build exoplayer using that factory method:

     SimpleExoPlayer player =
          new ExoPlayer.Builder(/* context= */ this)
              .setMediaSourceFactory(new RtspMediaSource.Factory().setDebugLoggingEnabled(true))
              .build()

Got you the logs that you asked for.
rtsp-logs-enabled.txt

@claincly I also found another possible problem. When using Basic authentication, the header is constructed as "Authorization: QWxhZGRpbjpvcGVuIHNlc2FtZQ=="
Shouldn't it be "Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==" as stated here https://en.wikipedia.org/wiki/Basic_access_authentication ?

Should it be: "Authorization: Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==", why missing word "Basic" ?