Finding out that your copy trips spam filters normally takes a burnt domain and a week of bad numbers.
Every message can now be checked before sending. Sellvance runs it through SpamAssassin and returns the score plus the individual rules it triggered — so you learn that it was the all-caps subject or the bare shortened link, and can fix that specific thing instead of rewriting blind.
Check individual messages from the message view, or check a step's template while you are still writing it. A score that is fine on the template is usually fine across the campaign; it is worth doing once per sequence, before launch.