Hi @ElNovi,
I asked our team about this and one of our community members was wondering if you’d be open to sharing your current configuration (Mattermost and system) for everything you’ve touched trying to make this work.
Also, for 5.3.1, http.ProxyFromEnvironment is used: app/notification_push.go:188 is part of sendToPushProxy which had called a.HTTPClient(...) ( app/app.go ) which uses NewHTTPClient ( utils/httpclient.go ).)