What 550 5.7.1 means
The message Gmail attaches to this code is “This email has been rate limited.”, as written on its reference page. The first digit says how final it is: a 5xx reply is permanent for that message, so the sending server gives up and returns a bounce. The enhanced status 5.7.1 says what class of problem it is: rate limit. The sender exceeded a published cap or was throttled. Slow down and spread the volume; the cap resets.
Why it happens
The sender pushed more mail at the receiver, in a burst or across the day, than it is willing to take from a sender it does not know well. The limit is not only the published cap: a new domain sending its first hundred messages in one hour is throttled where an established one would not be.
What to do first: Gmail throttled the sender. Slow the send, spread it over the day, and check Postmaster Tools for the reason.
Where warming fits
550 5.7.1 in this form is Gmail judging the sender's standing, and standing is built on engagement over time. Fix anything structural first (authentication, blacklists, list quality), cut the volume so the pattern stops, then rebuild the reputation the way it is earned: real engagement from real mailboxes over a ramp. That is what warming does, and a placement test shows when it has worked.
How to fix it, in order
- Slow the send and spread it across the day
- Check the provider's published limit
- Start outreach at 20 to 30 a day per mailbox and scale with placement, not with the cap
Related codes
- 550 5.7.233 (Microsoft): tenant external recipient limit
- 550 5.7.236 (Microsoft): onmicrosoft.com daily limit
- 550 5.2.2 (Microsoft): submission quota exceeded
- 550 5.7.1 (Gmail): policy prohibits the email
- 550 5.7.1 (Gmail): IP not authorized to send directly
More on Gmail
- Google Workspace emails going to spam: the Postmaster-led diagnosis, dashboard by dashboard
- Gmail and Yahoo bulk sender requirements: the rules behind Google's authentication and spam-rate rejections
- Google Workspace email warmup: the ramp against Google's own sending limits
- Emails suddenly going to spam: the six changes behind a sudden drop, and how to confirm each
Questions about 550 5.7.1
What does 550 5.7.1 mean?
Gmail returns 550 5.7.1 with the message "This email has been rate limited.": rate limited. The sender exceeded a published cap or was throttled. Slow down and spread the volume; the cap resets.
Is 550 5.7.1 a hard bounce or a soft bounce?
A hard bounce for that message: the 550 reply is permanent, and the message is not retried. Whether the address should be removed depends on the cause: here the fix is on the sending side, not the list.
How do I fix 550 5.7.1?
Gmail throttled the sender. Slow the send, spread it over the day, and check Postmaster Tools for the reason. Gmail's own reference for the code is linked on this page.
Does email warmup fix 550 5.7.1?
It is part of the fix. 550 5.7.1 in this form is about the sender's reputation with Gmail, and reputation is built through engagement over time, which is what warming supplies. Fix authentication and list problems first, then warm.