SMTP 550 5.7.1 · Gmail · Google Workspace

Our system has detected that this message is likely unsolicited mail

Gmail refused your message with 550 5.7.1 and a note about spammy content. Here is what the server is really objecting to, why it is usually reputation rather than wording, and the order to fix it in.

The bounce you received

550-5.7.1 [209.85.220.41] Our system has detected that this message is
550-5.7.1 likely unsolicited mail. To reduce the amount of spam sent to Gmail,
550-5.7.1 this message has been blocked. Please visit
550 5.7.1  https://support.google.com/mail/?p=UnsolicitedMessageError - gsmtp

What the server is actually saying

Gmail accepted the connection, read the message, and refused it at the content stage. The wording blames content, and that is the misleading part: Gmail applies this refusal when the combination of sender reputation AND content crosses a threshold. The same email from a warmed, authenticated domain is usually delivered. Treat it as a sender-reputation symptom with a content trigger, not a vocabulary problem.

Why it happens

• The sending domain is new or cold - no established history of wanted mail from it, so Gmail has nothing to weigh the content against.
• SPF, DKIM or DMARC is missing or misaligned, which removes the strongest signal that the mail is genuinely from you.
• Volume ramped faster than reputation. A domain that sent 10 mails yesterday and 500 today looks like a compromised account.
• The content carries classic filter triggers - many links, link shorteners, a single image and little text, ALL-CAPS or heavy punctuation in the subject.
• Recipients on a previous send marked it as spam. Complaint rate feeds directly into this refusal.

How to fix it, in this order

1. Authenticate first. Confirm SPF, DKIM and DMARC all pass for the exact sending domain - this is the single change that most often clears the refusal, and it costs nothing.
2. Stop sending from the domain for 24-48 hours. Continuing to push into a 550 hardens the reputation against you.
3. Warm the domain back up: low volume to engaged recipients, climbing gradually, until Gmail has recent evidence of wanted mail.
4. Only then rewrite the content - cut link count, drop shorteners, raise the text-to-image ratio, and remove ALL-CAPS and exclamation marks from the subject.
5. Re-send to a small, engaged segment before resuming the full list, and watch placement rather than assuming it is fixed.

Frequently asked questions

Does this mean my email content is actually spammy?

Usually not on its own. Gmail weighs content together with the reputation of the sending domain and IP. The same message from an established, authenticated domain is typically delivered, which is why rewriting the copy alone so often fails to clear it. Check authentication and sending history before rewriting.

Is 550 5.7.1 a hard bounce or a soft bounce?

It is a hard bounce - a permanent refusal for that message. Retrying the same message to the same recipient will be refused again. It is not a statement about the recipient address, though: the address is fine, it is your mail that was rejected.

How long does it take to recover?

If authentication was the problem, often within a day of fixing the DNS records. If the cause is reputation - a cold domain or a complaint spike - expect two to four weeks of consistent, low-volume, well-engaged sending before placement recovers.

Will a spam-score checker tell me if I will hit this?

Partly. A content checker catches the triggers you control in the message - trigger words, link count, text-to-image ratio - and that is worth doing before every campaign. It cannot see your domain reputation or your authentication, which are the more common causes of this specific refusal.

Related errors

• 554 5.7.1 — Message rejected due to content restrictions
• More bounce errors