diff --git a/swh/web/api/views/graph.py b/swh/web/api/views/graph.py
--- a/swh/web/api/views/graph.py
+++ b/swh/web/api/views/graph.py
@@ -140,6 +140,14 @@
     if request.GET:
         graph_query_url += "?" + request.GET.urlencode(safe="/;:")
     response = requests.get(graph_query_url, stream=True)
+
+    if response.status_code != 200:
+        return Response(
+            response.content,
+            status=response.status_code,
+            content_type=response.headers["Content-Type"],
+        )
+
     # graph stats and counter endpoint responses are not streamed
     if response.headers.get("Transfer-Encoding") != "chunked":
         return Response(
diff --git a/swh/web/tests/api/views/test_graph.py b/swh/web/tests/api/views/test_graph.py
--- a/swh/web/tests/api/views/test_graph.py
+++ b/swh/web/tests/api/views/test_graph.py
@@ -268,3 +268,25 @@
     assert resp.content_type == "application/json"
     assert resp.data["exception"] == "NotAcceptable"
     assert resp.data["reason"] == "Could not satisfy the request Accept header."
+
+
+def test_graph_error_response(api_client, keycloak_oidc, requests_mock):
+    _authenticate_graph_user(api_client, keycloak_oidc)
+
+    graph_query = "foo"
+
+    error_message = "Not found"
+    content_type = "text/plain"
+
+    requests_mock.get(
+        get_config()["graph"]["server_url"] + graph_query,
+        text=error_message,
+        headers={"Content-Type": content_type},
+        status_code=404,
+    )
+
+    url = reverse("api-1-graph", url_args={"graph_query": graph_query})
+
+    resp = check_http_get_response(api_client, url, status_code=404)
+    assert resp.content_type == content_type
+    assert resp.content == f'"{error_message}"'.encode()