You can check the auto-convert rules in MM5 > Options > Media Sharing > double-click the server > Auto-conversion tab : https://www.dropbox.com/s/x388jotms7zya ... 2.png?dl=0

Try to temporarily uncheck all checkboxes there to see if that makes any difference?
What is in the "Supported formats" section? It sounds like if the particular MP4 that you tested is not tracked as supported format by default?

If that doesn't help then please generate debug log (item 4b here: viewforum.php?f=30 )

That board is for MediaMonkey 4.

Check what Auto-Conversion rules you set for that particular file format. You may want to disable Auto-Conversion and see if it streams that way as well as try to play the files that fail within MediaMonkey itself.

First time I have tried Share Media with MM5 and running into some issues. Starting with Clean MM5 install 5.0.0.2314. All settings at default with Share Media enabled. Local firewall turned off. I am trying to stream mp4 movies to Amazon FireTV. I downloaded serval uPnP client apps for FireTV, including VLC. These clients can see the MM server and browse the categories, but when I try to play a movie all 3 clients give "unable to play" errors. I notice when this error happens in the MM5 app a window pops up "Unable to Decode this Format" when I click "Find missing codec" it directs me to download MediaMonkey 5 Codec Pack Trial. I download and install. Try again to play video from uPnP clients. Same error. Same message about "Unable to Decode" this time is directs me to "LAV Filters .741+"? I am doing something wrong in configuration? I left all defaults for sharing from clean install.

Here is encoding info for the mp4:
Video H264 (avc1) 640x480 23.00 fps, 1047 kbps
Audio AC3, 2 channel, 48000 Hz, 192 kbps

Going to movie this post to the uPNP/DLNA board thanks

First time I have tried Share Media with MM5 and running into some issues. Starting with Clean MM5 install 5.0.0.2314. All settings at default with Share Media enabled. Local firewall turned off. I am trying to stream mp4 movies to Amazon FireTV. I downloaded serval uPnP client apps for FireTV, including VLC. These clients can see the MM server and browse the categories, but when I try to play a movie all 3 clients give "unable to play" errors. I notice when this error happens in the MM5 app a window pops up "Unable to Decode this Format" when I click "Find missing codec" it directs me to download MediaMonkey 5 Codec Pack Trial. I download and install. Try again to play video from uPnP clients. Same error. Same message about "Unable to Decode" this time is directs me to "LAV Filters .741+"? I am doing something wrong in configuration? I left all defaults for sharing from clean install. Thanks