tmailrGuides
What to check before your first campaign
13 July 2026 · 2 min read · TMailr
The first campaign from a new domain or a new platform is the one that sets what follows. Receivers have no history for you, so they judge cautiously, and a bad start is slower to repair than it was to cause. Half an hour of checking beforehand is worth more than any amount of tuning afterwards.
Authentication, verified from the outside
Not from your configuration, which describes intent. Send one message to an address you can read and inspect the Authentication-Results header the receiving server wrote:
- spf=pass, and the domain it passed for is one you recognise.
- dkim=pass, signed by your domain rather than only by your platform.
- dmarc=pass, which means one of those aligned with your visible From address.
If DMARC fails while SPF and DKIM pass, the problem is alignment, and it is the commonest one: both legs authenticate for the platform’s domain and neither for yours.
The list
This matters more than the technical setup and gets a fraction of the attention. Sending to addresses that have not asked for it produces complaints, and complaints are the one number that is slow to recover.
- Everyone on it opted in, and you could show when and how.
- Nothing bought, rented, scraped or appended.
- Anything older than a year is either re-confirmed or left out.
- Obvious invalids and role addresses removed. info@ and admin@ generate complaints and rarely convert.
Warm up rather than launching
A new domain sending fifty thousand messages on its first day is indistinguishable, from the receiver’s side, from a compromised host. Start with hundreds to your most engaged recipients, double every day or two, and watch what happens before increasing again. Two weeks of patience buys a reputation; one impatient day costs a month.
The message itself
- Both unsubscribe headers, and a visible link as well.
- A plain-text part that makes sense on its own.
- A From: name and address a recipient will recognise.
- A physical postal address, which most jurisdictions require.
- Links on your own domain, not a shortener, which filters treat with suspicion.
Be able to see what happened
Publish DMARC with a reporting address before you send, not after. If something is failing alignment you want to learn it from a report on Tuesday rather than from a drop in opens three weeks later. And check the reporting address is one that can actually receive: if it is at another domain, that domain has to authorise it first, or the reports are dropped and it looks as though nothing is wrong at all.
More on guides
