Cannot play rtsp stream

I've integrated the library in a simple test app where I just want to play a rtsp stream. When I try to play this public rtsp stream (rtsp://demo:demo@ipvmdemo.dyndns.org:5541/onvif-media/media.amp?profile=profile_1_h264&sessiontimeout=60&streamtype=unicast) that uses DIGEST authentication I get a "DESCRIBE 503" error. I've posted some logs below, maybe they are more helpful. Sometimes the stream is played, but most of the times I get the error above. It's very strange.
Using rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov works fine.
Can someone have a look and point out the problem and possible solutions to fix it? Thank you
[rtsp-fail.txt](https://github.com/google/ExoPlayer/files/7307548/rtsp-fail.txt)