550 5.4.5: Daily sending limit exceeded

GmailSMTP

The error usually looks like this:

550 5.4.5 Daily user sending limit exceeded.

What it means

The Google account has sent more email in the past 24 hours than Gmail allows.

Common causes

  • Gmail and Google Workspace accounts have daily limits on messages and recipients.

How to fix it

  1. Wait up to 24 hours for the limit to reset.
  2. Use a dedicated email sending service for bulk or automated email.

Tools to help diagnose it

Email header analyzer

Trace your email’s delivery path and check SPF, DKIM, and DMARC authentication results

A free tool provided by Auth-Email

Auth-Email makes your Gmail, Outlook, or other OAuth 2.0 email account available to any IMAP, POP3, or SMTP email client — no app passwords or special configuration needed.

Read the docsTry Auth-Email →

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