MP4 files did not streaming to smart tv

This is a very commonly reported problem; search the forums for old threads.

Read your TV manual, and check the file type compatibility for USB and DLNA playback. It is very common for the supported formats to be completely different.

If your TV claims to support MP4 files, then you need to check what CODEC format is used in the MP4 container format, and make sure your TV supports that.

Then check to make sure that the Twonky Server on the MyCloud recognises your TV correctly, and uses the correct Receiver Type (check the Sharing tab (I think)).