Gmail and Google Workspace · permanent error
550 5.4.5: daily relay limit reached for a user
A Workspace user has sent more mail through smtp-relay.gmail.com today than the SMTP relay service allows for one user.
- Gmail
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 550 5.4.5
- Provider
- Gmail and Google Workspace
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
550 5.4.5 Daily SMTP relay limit exceeded for user.
What it means
The Workspace SMTP relay service limits how much each user can relay per day, as well as the total for the whole customer. This user has reached the per-user limit, so further relay mail sent as them fails until the limit resets. Google's relay error page refers admins to the SMTP relay service setting for the limits, or to their administrator for help. It tends to appear when an application or device relays everything under one user's address.
Common causes
- An application or device that sends all its mail under one user's address.
- A bulk send relayed through one account.
How to fix it
- 01Find the application or device sending as this user, from relay logs or Email Log Search.
- 02Spread automated mail across suitable sender addresses, or move bulk mail to a dedicated sending service.
- 03Check the SMTP relay limits in Google's documentation, and wait for the limit to reset.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- Gmail SMTP errors and codes (Google Workspace Admin Help)knowledge.workspace.google.com
- SMTP relay service error messages (Google Workspace Admin Help)knowledge.workspace.google.com
Related codes
- 550 5.7.1Daily relay limit reached for the customer.Your Google Workspace organization has relayed as much mail through smtp-relay.gmail.com today as its daily limit allows.
- 550 5.4.5Daily sending limit reached.The Gmail or Workspace account sending this message has reached its daily sending limit, so Google is refusing further mail from it for now.
- 550Mailbox unavailable.The receiving server permanently refused the message for this recipient: the mailbox does not exist, cannot be reached, or the server rejected the message by policy.
Further reading
All 108 Gmail codesEvery code in the wikiPaste your own bounce