400 Bad Request
The server will not process the request because of something it sees as a client error, such as malformed syntax or invalid framing.
4xx · Client error
Typical causes
Invalid JSON, missing or mistyped parameters, a malformed URL, or oversized or corrupt cookies. The response body usually names the problem.
On Bex
From the Bex API, a 400 means the request body or parameters were rejected: read the error message and check field names, types and whether the setting is supported.
Read the Bex guideDefined in RFC 9110, §15.5.1