Practical guides on deliverability, Google Workspace, Microsoft 365 and cold email infrastructure - written by engineers who fix this stuff daily, not content writers guessing.
Microsoft now gives a brand new tenant 10% of its sending quota for the first 30 days. Run the arithmetic and it probably changes nothing for you. The limit that actually stops a new setup is a different one, it is roughly eleven times tighter, and almost nobody mentions it.
Sanzid Sutrodor · Deliverability engineer · 10 min readA business owner's everyday client replies started bouncing with a spam rejection. He was about to start stripping images and attachments out of his emails. The real cause was three missing DNS records, visible to anyone with a free lookup tool, and nothing to do with what he had written.
Sanzid Sutrodor · 8 min readMicrosoft removed trap hit data from SNDS in July, weeks before Google retired its reputation dashboards. Both providers shrank what senders can see and if you send from Workspace or Microsoft 365, SNDS was never available to you anyway.
Sanzid Sutrodor · 11 min readMost accounts people call "suspended" were never suspended. Google shows five different suspension reasons - four you can fix today, and one that Google documents as unrecoverable by admins and by its own support team. Here is how to tell which one you have.
Sanzid Sutrodor · 15 min read
Google retired the Domain and IP Reputation dashboards. The Bad/Low/Medium/High rating is gone for good - but reputation data did not disappear with it. Here is what replaced the score, and where reputation still shows up.
Sanzid Sutrodor · 11 min readGoogle wants your spam rate under 0.10% and never above 0.30%. That is three complaints per 1,000 emails. Why adding mailboxes cannot fix it.
Sanzid Sutrodor · 8 min readMicrosoft published MC1454397: new tenants get throttled by age, trial tenants drop to 500 external recipients a day, and free EDU licences stop raising a quota. Here is what it does to a mailbox ramp.
Sanzid Sutrodor · 7 min readEveryone selling you something says warmup can be skipped, shortened, or bought. We sell pre-warmed mailboxes and we're still going to tell you: there is no shortcut through calendar time, and the teams that ramp slowest reach the highest sustained volume. Here's the mechanism, the numbers, and the exact schedule we run on every batch we ship.
Sheikh Rasel · 6 min readCheckers scan 50+ blacklists to scare you. In reality about three matter, one is defunct, and the two that decide your fate are not public - how to check and get delisted.
Sheikh Rasel · 6 min readThree DNS records decide whether your email reaches an inbox or evaporates into a spam folder. Most explanations either dumb them down until they're wrong, or drown you in RFC jargon. This one does neither. By the end you'll be able to read your own records - and spot the one mistake that quietly breaks everything.
Sheikh Rasel · 8 min readEvery limits article lists the same documented caps and stops there, which is like describing a country by its border fence. The documented numbers below are real and verified - but you will hit the undocumented reputation ceiling at roughly 2% of the official limit, and understanding that gap is the entire game. Numbers first, then the math that actually plans a campaign.
Sheikh Rasel · 5 min readOpen rates sliding week over week is the most common message we get on WhatsApp – and the most commonly misdiagnosed. Teams reach for the visible things first: rewrite the copy, buy new domains, switch tools. Usually the real cause is quieter, and usually it’s one of seven. Work through these in order. They’re sorted by […]
Sheikh Rasel · 5 min read"My mailbox is burned" is the most common self-diagnosis in cold email - and about half the time, it's wrong. Sometimes the domain is burned (different fix).
Sheikh Rasel · 4 min readEverything in these articles is something we do for clients daily - setup, authentication, warmup, fixes. Skip the DIY and have it done free with your mailboxes.
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