Very good questions:
Did I try different stream format? : I can not change stream format because it is coming from a paid IPTV Server in MP4. My Dreamlink boxes using same server play VOD fine, all Buzz boxes loaded with Buzz5 firm. will not play the VOD. Live Tv is fine, the issue seems to be with the built in Media Player.
I have taken the BuzzTV boxes to another state, connected to a different ISP, same issue.
So, this leads back to communication between the Buzz & the Server, selecting Play on any VOD movie results in a spinning circle non stop, if you stop it, the progrsm locks up and error message shows up to close the Buzz app.