Most likely the file is not in the correct format.
WAV files can have multiple compression methods, including MP3.
PCM (Pulse Code Modulation) is the only one supported by the DeepBot currently. Fortunately, it's the most common WAV format, so most .WAV files just work.
There are quite a few tools that can convert audio files. For example,
Switch Audio can convert between formats (even in the free version). You'll need need to get your file into a standard, PCM encoded WAV file for it to work with DeepBot.
