docs(obj): add troubleshooting on sse with aes 256 (#5777)

* docs(dwh): preview MR for DWH

* docs(obj): update

* docs(obj): update

Author: SamyOubouaziz

pages/object-storage/troubleshooting/400-error-aes256.mdx

@@ -0,0 +1,47 @@
+---
+title: I get 400 Bad Request errors when uploading objects
+description: Solve 400 Bad Request errors when uploading objects with AES256 encryption headers
+tags: sse amazon-s3 aes 256 error put header server side encryption fail reject
+dates:
+  validation: 2025-11-07
+  posted: 2025-11-07
+---
+import Requirements from '@macros/iam/requirements.mdx'
+
+
+<Requirements />
+
+- [Owner](/iam/concepts/#owner) status or [IAM permissions](/iam/concepts/#permission) allowing you to perform actions in the intended Organization
+
+## Problem
+
+When uploading an object, I get an error similar to the following:
+
+```bash
+HTTP 400 Bad Request: InvalidArgument.
+```
+
+## Cause
+
+Scaleway Object Storage previously accepted requests containing the `x-amz-server-side-encryption: AES256` header without enforcing encryption, returning a successful `HTTP 200 OK` response.
+
+Requests with this header are now explicitly rejected with an `HTTP 400 Bad Request: InvalidArgument` error, as AES256 server-side encryption is not currently supported by Scaleway Object Storage.
+
+## Solution
+
+Remove the `x-amz-server-side-encryption: AES256` header from your requests. 
+
+## Going further
+
+Refer to the [dedicated documentation](/object-storage/api-cli/enable-sse-c/) for comprehensive information on how to encrypt objects using SSE-C.
+
+- If you did not manage to identify the error and solve it by yourself, [open a support ticket](/account/how-to/open-a-support-ticket/), and provide as many details as possible, along with the necessary information below:
+    - Object Storage Endpoint (e.g. `s3.fr-par.scw.cloud`)
+    - Bucket name
+    - Object name (if the request concerns an object)
+    - Request type (PUT, GET, etc.)
+    - HTTP status code
+    - Date and time (timestamp)
+    - User-agent (SDK, client, console, etc.)
+    - Transaction ID (if possible)
+    - Log / trace of the error (if possible)

pages/object-storage/troubleshooting/index.mdx

@@ -62,6 +62,7 @@ productIcon: ObjectStorageProductIcon
 - [I cannot access my data](/object-storage/troubleshooting/cannot-access-data/)
 - [I cannot delete my bucket](/object-storage/troubleshooting/cannot-delete-bucket/)
 - [I cannot restore my objects from Glacier](/object-storage/troubleshooting/cannot-restore-glacier/)
+- [I get 400 Bad Request errors when uploading objects](/object-storage/troubleshooting/400-error-aes-256/)
 - [I lost access to a bucket after applying a bucket policy](/object-storage/troubleshooting/lost-bucket-access-bucket-policy/)
 - [I am experiencing performance issues](/object-storage/troubleshooting/low-performance/)
 - [Lifecycle rules issues](/object-storage/troubleshooting/lifecycle-rules-issues/)