The following piece of code (Vala)

rtsp_factory = new Gst.RTSPServer.MediaFactory();
rtsp_factory.set_launch(pipeline_description);
rtsp_factory.set_shared(true);
rtsp_server.get_mount_points().add_factory("/", rtsp_factory);

Will cause Not Found error in the client

vagrant@trusty64:/vagrant$ gst-launch-1.0 playbin uri=rtsp://example.com:6000/
Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Progress: (open) Opening Stream
Progress: (connect) Connecting to rtsp://plumber1.stag.srv.radiokit.org:6000/
Progress: (open) Retrieving server options
Progress: (open) Retrieving media info
Progress: (request) SETUP stream 0
ERROR: from element /GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0/GstRTSPSrc:source: Could not write to resource.
Additional debug info:
gstrtspsrc.c(6450): gst_rtspsrc_setup_streams (): /GstPlayBin:playbin0/GstURIDecodeBin:uridecodebin0/GstRTSPSrc:source:
Error (404): Not Found

In the debug info at the server the following information appears:

0:00:24.850234488  4980       0xd22540 ERROR             rtspclient rtsp-client.c:641:find_media: client 0xd588b0: no factory for path /stream=0
0:00:24.850375091  4980       0xd22540 ERROR             rtspclient rtsp-client.c:1993:handle_setup_request: client 0xd588b0: media '/stream=0' not found

The issue does not happen if mountpoint is set to "/something" instead of "/". It seems that there's a fault in function that extracts mount point name from media URI.