550 5.1.2: Recipient domain does not exist
550 5.1.2 means the domain after the @ cannot be found or cannot receive mail. The part before the @ is never even checked. Fix the domain or drop the address.
- Bounce type
- Hard bounce (permanent)
- Usually caused on
- The recipient's side
- Terlido report label
- Invalid recipient
What the standard says
RFC 5321 defines 550 as "mailbox unavailable". RFC 3463 defines 5.1.2 as "Bad destination system address": the destination system named in the address does not exist or cannot accept mail. This is the same family as 5.1.1, but it points at the domain half of the address instead of the mailbox half.
What the mailbox providers say
- Gmail (553 5.1.2): “We weren't able to find the recipient domain...” Source
Common causes
- A typo in the domain, such as gmial.com instead of gmail.com or a missing letter in a company name.
- The company shut down or let its domain expire, so the domain no longer resolves.
- The domain exists but has no MX record, so there is nowhere to deliver mail.
- A website address pasted into an email column, for example a name followed by a .com that is not a mail domain.
- Gmail reports this condition with reply code 553 instead of 550. The meaning is the same.
- A domain in the list that belongs to a free email service with a misspelled name, which often comes from forms typed by hand.
- A subdomain that was never set up for mail, for example mail.company.com used where company.com is the real mail domain.
How to fix it
- Look at the domain part of the address and fix any obvious typo against the company's real site.
- Look up the MX records for the domain. If none exist and the website is gone too, remove the contact.
- Search your list for common provider typos and correct them in bulk before you import again.
- Drop any row where the domain is a bare website with no mail service behind it.
- Compare the domain with the company's website. If the site uses a different domain for email, use that domain instead.
- After you correct a domain, check the MX record again before you add the contact back to a campaign.
Is it a deliverability problem?
This code is almost always a list quality problem, not a reputation problem on your side. It still counts as a hard bounce, though, and a batch of them from one import shows that the list was not cleaned. Fix the import step so typo domains are caught before sending. Because the receiver never reached a mailbox, nothing about your message was judged. The only lesson is about your data. Still, bounces of any kind add to the same hard bounce count, so a messy import can cost you the same amount of reputation as a bad message.
How Terlido handles it
When a bounce message for this code arrives in a connected mailbox, Terlido reads the status code. An enhanced code that starts with 5 is a hard bounce. In the campaign Reports tab this one is grouped as "Invalid recipient".
On a hard bounce Terlido adds the address to the workspace blocklist with the reason "hard bounce", so no campaign emails it again. The lead stops in that campaign as bounced, its lead score goes down by 15, and the bounce counts toward the campaign's bounce rate.
Once a campaign has at least 20 sends, it pauses itself when hard bounces divided by sends goes over the campaign's maximum bounce rate. The default is 5%. If the cause was on your side and you fixed it, you can remove the entry on the Blocklist page of your account settings and try again.
Check the domain behind the bounce
The free domain checker runs live SPF, DKIM, DMARC, MX and blocklist lookups and explains each result in plain English.
Free tools that help
- MX lookupShow a domain's mail exchanger records.
- Email list format checkerReview CSV structure, empty addresses, and basic email syntax without contacting mail servers.
Related error codes
- 550 5.1.1: Recipient address does not exist
- 553 5.1.3: Recipient address is not valid
- 550 5.1.10: Recipient not found