Hey Mark, so I personally use ActiveCampaign as an affiliate, and I haven’t had any issues.

They don’t technically allow it, so here’s the precautions I take:

– Don’t send affiliate links for a few weeks to warm up your account (use welcome sequences, etc to prove you’re not a spammer)
– Back up your lists frequently (in case you do get banned)
– Link to a bridge page or blog post, not a direct affiliate link
– Cloak your affiliate links / add a disclosure to your emails if you are going to direct link

And if you don’t want to deal with this, Aweber and GetResponse are two autoresponders that allow affiliates. I liked GetResponse a bit more personally!

Hope this helps