I recently took over our Marketo instance. Last summer I noticed some deliverability issues and we discovered we were on about 12 blacklists. We couldn't imagine why, as we've never purchased lists, all our emails are relevant to the audience (niche product/audience), and no overuse of SPAM trigger words (free, loads of exclamations, etc). We thought, perhaps, that it was because we were on shared IP, and have since moved to a private IP, hoping that would resolve the issue.
But the more I've been building programmes and testing emails, I'm still seeing issues...one obvious one is that that valid emails frequently get marked as Marketing Suspended...for example my own private gmail–an active account that I'm in daily. But according to Marketo it's regularly soft-bouncing ... which is why I have to keep manually changing my Marketing Suspended status to false.
Anyone else experienced this? Do I need to increase the soft bounce threshold. Are there any ramifications of this I need to be aware of?
There are dozens of threads on managing deliverability.
Your particular Marketing Suspended case indicates that there is a flow that is marking soft bounces as suspended. Check your record's logs. Marketo only sets Email Suspended as a system flow.
You can end up on blacklists because lists get old, some leads become spam traps, and servers automatically mark you as spam eventually. You can remove yourself if you go to some of the blacklists and fix some issues.