550 5.4.5: daily user sending limit exceeded
Your Gmail or Google Workspace account has hit Google's daily sending limit, so new messages are refused for up to 24 hours.
550 5.4.5 Daily user sending limit exceeded.
Start of Gmail's text, as listed in Google's SMTP errors reference. A similar 5.4.5 text covers the daily SMTP relay limit. Gmail's replies can run over several lines; RFC 5321 says every line except the last starts with the code followed by a hyphen, so the same error can appear as 550-5.4.5.
What 550 5.4.5 means
This error comes from your own provider, not from the recipient. Google limits how many messages each account can send per day and how many recipients each message can have. Google's reference lists two 550 5.4.5 texts: "Daily user sending limit exceeded" and, for organizations that route mail through Google's SMTP relay service, "Daily SMTP relay limit exceeded for user".
Google's published limits for Google Workspace include 2,000 messages per day per user account (1,500 for mail merge and 500 for trial accounts), and 2,000 recipients per message with a maximum of 500 external recipients. Daily limits apply over a rolling 24-hour period, not a set time of day. After reaching a limit, users can't send new messages for up to 24 hours, though they can still receive mail. Trial limits aren't raised during the free trial: after a trial converts to a paid subscription, Google raises them automatically once the domain has paid at least $100 USD in total, which can take up to 75 days after reaching that threshold. Limits can change without notice.
If you hit the limit without sending much yourself, treat it as a warning sign: a compromised account or a misbehaving app may be sending in your name. Change the password, review connected apps, and check the Sent folder.
Likely causes
- Sending a large mailing from a personal or Workspace mailbox.
- An app, script or device sending through the account.
- A compromised account sending spam.
- Using a trial account, which has lower limits.
How to fix it
If you sent the message
- Wait: sending resumes after the suspension period, up to 24 hours.
- Use a dedicated email-sending service for newsletters and bulk mail.
- Check the Sent folder and connected apps for anything you didn't send; reset the password if in doubt.
If you're the recipient or their admin
- No action needed: the limit is on the sender's account.
Frequently asked questions
How long until I can send again after 550 5.4.5?
Google says users can't send new messages for up to 24 hours after reaching a limit, and that daily limits run over a rolling 24-hour period. You can still receive mail in the meantime.
Can an admin raise the limit?
Not by request: Google's published limits are fixed per account type. Former trial accounts get the higher limits automatically once the domain has paid at least $100 USD in total, which Google says can take up to 75 days. For bulk mail, use a sending service built for it rather than a mailbox.
Sources
- Gmail SMTP errors and codes (Google Workspace Admin Help)
- Gmail sending limits in Google Workspace (Google Workspace Admin Help)
- RFC 5321, section 4.2: SMTP replies (multiline reply format)
Provider messages are quoted as the provider publishes them. Servers can change their wording, so the bounce you received may differ slightly.
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