550 5.4.5 Gmail bounce: daily sending limit
What 550 5.4.5 means
The sending account reached its daily Gmail sending limit, so it cannot send more mail until the limit resets.
Message text
Daily user sending limit exceeded…
This is an excerpt: the provider's documentation shortens the message. Full text: provider documentation
Common causes of 550 5.4.5
- Daily sending limit for the user or SMTP relay was exceeded
How to fix 550 5.4.5
- Wait for the daily limit to reset, then send again.
- Spread larger sends over several days or use a dedicated bulk sending service.
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How to read 550 5.4.5
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, 5.4.5, 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 4 is network and routing: a problem reaching or routing to the destination. 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
- 5.4.4 SMTP: unable to route
- 5.4.1 Microsoft: relay access denied
- 5.4.1 Microsoft: recipient rejected
- 5.4.14 Microsoft: routing loop
- 5.4.300 Microsoft: not delivered in time
- 5.4.8 Microsoft: mx not in mta-sts policy
FAQ
What does 550 5.4.5 mean?
The sending account reached its daily Gmail sending limit, so it cannot send more mail until the limit resets. This is a permanent failure.
How do I fix 550 5.4.5?
Wait for the daily limit to reset, then send again. Spread larger sends over several days or use a dedicated bulk sending service.
Is 550 5.4.5 permanent, and should I retry?
550 5.4.5 is a permanent failure, so retrying the same message will fail again. Fix the cause first, then send a new message.