Why Do I Keep Getting Emails From Unknown Senders?

Why do you keep getting emails from unknown senders? The honest answer is that "unknown sender" describes five different situations, and each needs a different response. A spoofed From line looks like mail from a stranger but is a phishing attempt. Typo-neighbour mail is meant for someone else and should not be marked as spam. A signup bomb — dozens of confirmation emails arriving in a short window — signals active account fraud using your address.

Before you block or delete, spend two minutes identifying which of the five you have. Blocking a spoofed address does nothing because the address is fabricated. Marking typo-neighbour mail as spam damages an innocent sender's reputation. This post is the diagnosis. For the step-by-step on stopping each type, the sibling guide on how to stop emails from unknown senders covers the platform controls.

What "unknown sender" means — five causes#

Look at the content, the sender domain, and the timing — not just the display name.

Fix 1: Typo-neighbour mail — email meant for someone else#

Typo-neighbour mail arrives when someone with an address close to yours gives out the wrong one. You receive their receipts, bank notifications, or appointment reminders. It is not spam, and marking it as such harms the legitimate sender.

1. 1

   Do not engage with the content

   The emails may contain a stranger's private information. Read only enough to confirm the cause, and do not click any links. You are not the intended recipient.

2. 2

   Tell the sending company

   Reply to the company — not the account holder — and say you are not the person named. Most services will remove the wrong address, which stops further mail.

3. 3

   Filter the domain while you wait

   Create a filter routing that company's domain to a folder labelled "not mine" until notifications stop. Do not report as spam; this is a real sender delivering to the wrong address.

Fix 2: Spoofed From addresses — when the sender field is forged#

A spoofed From address means the sender field has been fabricated to look like a bank, courier, or colleague. Blocking it does nothing — the actual sending infrastructure differs from the visible From field, and the next message will use a different fabricated address.

1. 1

   Check the authentication headers

   Open "Show original" in Gmail. A genuine sender passes SPF, DKIM, and DMARC. A spoofed From line fails SPF or carries no DKIM signature — that failure confirms the cause.

2. 2

   Report phishing, not spam

   In Gmail, use the three-dot menu and choose "Report phishing". This flags the sending infrastructure, not just the fabricated address — it is the stronger action against forged mail.

3. 3

   Do not reply or click any link

   Reply-to addresses in spoofed mail route to the attacker. Do not click an unsubscribe link either — there is nothing legitimate to unsubscribe from.

Fix 3: Scraped address, old list, or signup bomb#

These three causes share a root: your address is circulating without your consent. A scraper lifted it from a public post. A list you joined years ago was sold when the company was acquired. Or someone is registering accounts at many services using your address, hoping you click "confirm" on one by mistake — the signup bomb floods your inbox so a genuine fraud confirmation gets buried in the noise.

1. 1

   For a signup bomb: filter first, do not click

   Create a temporary filter to send any message with "confirm" or "verify" in the subject to a folder. Let the wave pass, then delete the folder. Change passwords on your most important accounts and enable two-factor authentication.

2. 2

   For a scraped address: block the domain, not the sender

   Scraped-address campaigns rotate through many addresses under one domain. Blocking a single sender leaves the next rotation through. Block everything from the whole sending domain and report as spam to feed your provider's reputation system.

3. 3

   For an old list under a new brand: trace the footer and unsubscribe

   The message footer will usually name the company now operating the list. Use the one-click unsubscribe near the sender name, not a link buried in the body. If mail still arrives after ten days, block the sending domain.

How to tell which cause you have#

Start with the content. Mail containing another person's name and account details is typo-neighbour mail. A sudden cluster of confirmation emails you never requested is a signup bomb. For everything else, check the authentication headers: a spoofed From line fails SPF or has no DKIM signature. A sender that passes authentication but is still unrecognised is either an old list or a scraped-address campaign — look for an unsubscribe link and a company name in the footer to tell them apart.

Preventing it#

• Use a unique alias or plus-address for each service you sign up with — one address per service means you can trace exactly which one leaked or sold your contact.
• Do not post your primary address on public forums, GitHub profiles, or website contact pages; scrapers harvest from those sources automatically.
• When you reach a scraped-address sender, block the domain rather than a single address — a rotation will not reset it.
• Watch for a burst of confirmation emails arriving in a short window; that pattern is a signup bomb, not a filtering failure.
• Check your address against a breach-notification service periodically; Have I Been Pwned searches your address across thousands of known breach databases.

Where AI Emaily fits#

An address that has been scraped or used in a signup bomb stays in circulation permanently — unsubscribing removes you from one list and rarely from the source that distributed it. AI Emaily's cold-email filter identifies unsolicited outreach by sender behaviour and domain pattern rather than a single address, so a sender rotating through new addresses under the same domain gets routed out without a new block rule each time. We build AI Emaily; the spam-protection page describes how the filter works if you want to check the mechanics first.