Why emails go to spam
Messages are filed as spam because of the sender's history, the list, the content, the authentication or the volume pattern, roughly in that order of weight. Working out which one applies to you is a matter of elimination rather than of buying a better tool.
On this page
Nobody outside a receiving mail server decides where a message is filed, and nothing on this page will claim otherwise. What can be described honestly is what those servers consistently react to, and which of those things a sender can change.
Does the sender’s history matter most?
Yes, more than anything else. A sender with a record of messages people wanted is treated differently from one with a record of complaints, and a sender with no record at all is treated as the unknown quantity it is.
This is why a brand new domain performs badly even with perfect copy. The message is fine; the sender is a stranger.
How much of it is the list?
A great deal. A list of people who asked to hear from you behaves completely differently from a list bought from somebody, and the difference shows up as complaints within hours.
Bought and harvested lists are also full of addresses that no longer exist, and a burst of failures to dead addresses is one of the clearest signals a sender can produce. PhantomFox does not sell, rent or supply lists, and does not send to a list it can see was harvested, for exactly this reason.
What about the content itself?
Less than most people think, and not in the way the folklore says. Single words rarely decide anything on their own; what matters is whether the whole message resembles messages recipients have previously marked.
Links to domains with bad reputations, heavy image only layouts and messages that hide who sent them all contribute. Writing plainly and saying who you are costs nothing and helps.
| Cause | What it looks like from your side | What actually changes it |
|---|---|---|
| Sender history | good copy performing badly | time, or a sender already warm |
| The list | complaints within the first hour | a list people opted into |
| Content | one campaign filed, others fine | plain writing, honest links |
| Authentication | everything filed, everywhere | published records, or a supplied identity |
| Volume pattern | fine at small size, bad at scale | a warm sender rather than a ramp |
How do you find out which one is yours?
By elimination, in the order of the table. If everything you send is filed everywhere, look at authentication first, because that is a yes or no question with an answer you can check.
If one campaign is filed and the rest are fine, the content or the list segment is the cause. If small sends are fine and large ones are not, the sender was never warm enough for the volume you are pushing through it.
What can a sending service honestly promise?
That the sender is warmed before you touch it, that the authentication is in place, and that the unsubscribes and the spam reports a campaign generates land on our sending infrastructure rather than on an address of yours. That is the useful part, and it is the part a provider controls.
What no provider controls is the decision a receiving server makes about an individual message, and any promise about that is worth nothing. If you want to see what actually happens to a real send, read how to test a campaign without risking a domain and the page on deliverability testing for inbox placement.
Next, read what happens when a sending account is suspended and what email warm up is and can you skip it, or browse the answers hub.