diff --git a/src/together/filemanager.py b/src/together/filemanager.py
index ac907985..b58d873e 100644
--- a/src/together/filemanager.py
+++ b/src/together/filemanager.py
@@ -378,7 +378,8 @@ def upload(
 
             if not callback_response.status_code == 200:
                 raise APIError(
-                    f"Error code: {callback_response.status_code} - Failed to process uploaded file"
+                    f"Error during file upload: {callback_response.content.decode()}, headers: {callback_response.headers}",
+                    http_status=callback_response.status_code,
                 )
 
             response = self.callback(f"{url}/{file_id}/preprocess")