Resolved!

I was facing a "400 Bad Request" error while trying to place market orders using the Binance Testnet API. After double-checking my API keys, request parameters, and signature generation, I finally discovered the issue: the system time on my Windows machine was not accurate.

Binance requires an exact timestamp when sending requests, as it's used for validating the HMAC SHA256 signature. If the system clock is even a few seconds off, the generated signature becomes invalid, leading to a 400 Bad Request error.

ptbtime1.ptb.de

This is one of the Physikalisch-Technische Bundesanstalt (PTB) time servers, known for its high precision.

Thanks!!