MissingContentLength Issue While Using S3

[rojinebrahimi]

Hey everyone!

I have encountered this error using Ceph S3 as snapshot store for Evidently AI. I was uploading the generated report and apparently, I got a 500 error while uploading.

2026-02-12T20:41:11Z ERROR litestar Uncaught exception (connection_type=http, path='/api/v2/projects/019c43a8-c3df-76db-ab29-1be317c39a0e'):
Traceback (most recent call last):
File "/usr/local/lib/python3.11/site-packages/s3fs/core.py", line 168, in _error_wrapper
return await func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/aiobotocore/context.py", line 36, in wrapper
return await func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/aiobotocore/client.py", line 424, in _make_api_call
raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (MissingContentLength) when calling the PutObject operation: Unknown

Has anyone resolved this issue already? I am not sure if there are any fsspec related parameters for this.

Thanks in advance.