What is "Our services aren't available right now" error?

I’m developing embedded system to access openai by chatgpt api.
My system works as:

  1. connect to WIFI.
  2. connect to ‘openai.com’ server (port 443) by SSL.
  3. send HTTP format data to open ai.

I got error message as below,

HTTP/1.1 400 Bad Request
Transfer-Encoding: chunked
Date: Tue, 04 Apr 2023 06:37:33 GMT


Our services aren't available right now

We're working to restore all services as soon as possible. Please check back soon.

0rsUrZAAAAADdakTzaBfBQa3huKh8gkEdU0VMMjFFREdFMDEyMABFZGdl 0 ========================================================================== What is this error message?

What browser/device you are using?

My emedded system connect to ESP32 wifi module.