Malformed HTTP message when using arecord to send audio from Raspberry Pi

Hello -- when trying to send live audio to vosk-server kaldi-en running on a remote server using the following code on the rPi client...

`arecord --buffer-time=5000000 -D plughw:2,0 -f cd -t raw | nc -N 10.0.1.10 2700`

...I get the following error on the client:

```
Recording raw data 'stdin' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
HTTP/1.1 400 Bad Request
Date: Mon, 01 Feb 2021 04:30:50 GMT
Server: Python/3.7 websockets/7.0
Content-Length: 23
Content-Type: text/plain
Connection: close

Malformed HTTP message
```

The server is definitely up and running, but seems to always send a 400 error. I am using the final line of code on this Kaldi documentation page as my example, because it's all I was able to find:

https://kaldi-asr.org/doc/online_decoding.html

I am unable to find any additional information in the server logs. Any idea how I can troubleshoot this? Thanks!