It is kind of strange for me. Everything looks fine, the way it should be. But it refuses to play some videos, citing " communication error with server", while playing other videos on the the same server as normal.
Those videos Xbox 360 plex player refuse to play, they play just fine elsewhere, on iPads and Phones.
I am noticing the same issue when using the DVR function. I can record to the Shield and it seems to have no problem running recorded episodes on other Android devices, but I receive the same error when trying to watch through the XBox 360. Hopefully it is a known issue that can be corrected in future versions.