We employ CFMAIL in a loop to send bursts of 200 messages via Amazon Simple Email Service - every few minutes to an opt-in subscriber list of approx 80K records.
In this way our campaigns take a few hours to complete but our reception and reputation rates remain high. Until recently…
With yesterday’s campaign, some MTAs like AOL / Spectrum / Roadrunner have been pushing back against our traffic, complaining that we (via SES) are making too many connections at once.
Our AWS limit is currently 28 per second. But the complaints come from the down-line MTAs, like the big conglomerate combo that serves AOL, Yahoo, Comcast, Spectrum, Roadrunner and others. So we’re trying to throttle it on our end first, to see if that helps.
The fun part is that these MTA postmasters never cite any thresholds or policies they follow, for fear of tipping off spammers to the specifics. So they just say stuff like “It’s wrong” or “It’s too high, so lower it and try again”.
Yes, I suppose Occam’s razor would point to your solution as the logical first step.