wit.wit.WitError: Wit responded with status: 400 (Bad Request)

[SanatMoharir]

Hi, whenever I am trying to run the code the following error is appearing:
audio_johnnys_greeting.wav
Traceback (most recent call last):
File "pizzawit.py", line 95, in
resp = do_wit_natural_language_processing(audio_file)
File "pizzawit.py", line 43, in do_wit_natural_language_processing
resp = client.speech(f, None, {'Content-Type': 'audio/wav'})
File "/home/sanat/anaconda3/envs/tfg/lib/python3.6/site-packages/wit/wit.py", line 88, in speech
data=audio_file, headers=headers)
File "/home/sanat/anaconda3/envs/tfg/lib/python3.6/site-packages/wit/wit.py", line 41, in req
' (' + rsp.reason + ')')
wit.wit.WitError: Wit responded with status: 400 (Bad Request)

I have created the wav files using text to speech for both, bot and client. And successfully created the wit server token.

Can you please help me with this one?