The VideoLAN Forums

I am accessing my music library on VLC for IOS from my UPNP server. When selecting "airplay" to stream to other devices, this does not work for me. It works for local content, but cannot stream via airplay for media from UPNP server.

Is this a bug or just not supported?

It is actually supported, but might be that your WIFi connection is not reliable or fast enough to serve both input and output streams at the same time, especially on older iOS devices.