> I am the one who is a client of sendgrid. Before subscribing to their service (with low volume it is free) > many of my messages were rejected. They provide legitimacy.
So the problem here is actually that a spammer whines about being spammed? :D But this does confirm my idea that one should just blanket blacklist these networks, because they mostly harbour clients that were blocked and have no where else to go any more. I do not recommend using sendgrid. Going there with your legitimate services is like having your products manufactured by forced child labour which is maybe legal in that part of the world, but it is still something you do not want to be associated with.
