Smartphone content cannot be played when connected using the Media Transfer Protocol (MTP).

Connect your smartphone using the Mass Storage Class (MSC) setting if it is supported, then try again playing content from the smartphone.

NOTE: When using an MSC connection, audio files may not be played depending on the file format.

If the name of the folder or file is long, it may take some time to start playback. Assign a short name using only alphabet characters and numbers.