Getting "0 DC downstream_remote_disconnect - " when trying to upload multipart file

Hi,
We are giving a try to Istio on our existing application.
We are using version 1.9.2 of Istio.
We are just using sidecar injection to start with it.
I’m trying to upload a file with an http post with multipart/form-data.
I have "POST /v0/documents/upload HTTP/1.1" 0 DC downstream_remote_disconnect - " on the Istio proxy logs of the target service.
Everything seems to work in our applications apart from this call.
What am I missing?