550 5.1.1 Gmail bounce: gmail address not found
What 550 5.1.1 means
The Gmail address does not exist, so Gmail permanently refuses the message.
Message text
The email account that you tried to reach does not exist…
This is an excerpt: the provider's documentation shortens the message. Full text: provider documentation
Common causes of 550 5.1.1
- Typo or stray space in the address
- Account was closed or never existed
How to fix 550 5.1.1
- Check the recipient address for typos and stray spaces.
- Remove the address from your list if it does not exist.
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How to read 550 5.1.1
The first part, 550, is the SMTP reply code. Requested action not taken, mailbox unavailable: the mailbox does not exist, is not allowed, or the message was refused for policy reasons. Replies that start with 4 are temporary and replies that start with 5 are permanent (RFC 5321 §4.2.1).
The second part, 5.1.1, is an enhanced status code (RFC 3463 §2) written class.subject.detail. Class 5 is a Permanent failure (5xx): the command was rejected and the sender should not repeat it unchanged (RFC 5321 §4.2.1; RFC 3463 §2).. Subject 1 is addressing: a problem with the recipient or sender address. The detail number refines the subject, and providers may define details of their own, which is why one code can read differently at Gmail, Microsoft and Yahoo.
Do not keep resending the same message: a permanent failure repeats until the cause is fixed. Correct the cause, then send a new message.
Official source: knowledge.workspace.google.com. Last verified 2026-10-20.
Related guides
- How to set up MX records (priorities, null MX, migration)
- MX host does not resolve: causes and how to fix it
- Null MX (RFC 7505): publish it for domains with no mail
Related codes
- 5.1.1 SMTP: bad destination mailbox
- 550 5.1.1 Microsoft: bad mailbox address
- 5.1.2 SMTP: bad destination system
- 5.1.3 SMTP: bad address syntax
- 5.1.10 SMTP: recipient has null MX
- 550 5.1.10 Microsoft: recipient not found
FAQ
What does 550 5.1.1 mean?
The Gmail address does not exist, so Gmail permanently refuses the message. This is a permanent failure.
How do I fix 550 5.1.1?
Check the recipient address for typos and stray spaces. Remove the address from your list if it does not exist.
Is 550 5.1.1 permanent, and should I retry?
550 5.1.1 is a permanent failure, so retrying the same message will fail again. Fix the cause first, then send a new message.