Grafana_image_renderer Issue

I’m using Grafana (version 8.3.1) with Prometheus (version 2.31) in linux ubuntu 20.04.
Grafana and prometheus run in docker containers on the same network, and my host is behind a proxy (even Docker and containers already have proxy configuration).

However, I recently installed another docker container for remote rendering, following the configuration “Run in Docker” found here: GitHub - grafana/grafana-image-renderer: A Grafana backend plugin that handles rendering of panels & dashboards to PNGs using headless browser (Chromium/Chrome).

The problem is that every image rendered in the alerts comes out as in the image below, with the message “Error updating options” and as if it were trying to access some page without success.
Has anyone faced this problem? Any tips?