Gmail Error: 4.7.28 – Unusual Rate of Unsolicited Mail Detected

Modified on: Tue, 30 Jun, 2026 at 11:31 PM

EMAIL DELIVERABILITY

Gmail Error 4.7.28: Unusual Rate of Unsolicited Mail

What this temporary Gmail rate limit means, why it happens, and how to get your sending back to normal.

What You'll Learn

If you see the error below while sending emails to Gmail recipients, it means Gmail has temporarily limited emails from your sending IP due to unusual sending behavior.

Table of Contents

What Does This Error Mean?

Is My IP Blocked?

Why Did This Happen?

How to Fix This Issue

How Long Does Recovery Take?

Frequently Asked Questions

What Does This Error Mean?

If you see the error below while sending emails to Gmail recipients, it means Gmail has temporarily limited emails from your sending IP due to unusual sending behavior:

4.7.28 Gmail has detected an unusual rate of unsolicited mail originating from your IP

Good to Know

This is not a permanent block or blacklist. Gmail uses automated systems to protect its users from spam. When it detects a sudden spike in email volume or patterns that look unusual, it may temporarily slow down or defer emails from that IP to prevent potential abuse.

Is My IP Blocked?

No. This error indicates a temporary rate limit, not a permanent IP block.

The 4.x.x error code means Gmail is deferring emails, not rejecting them.
Once sending behavior improves, Gmail usually automatically removes the restriction.
No manual delisting request is required.

Why Did This Happen?

This error commonly occurs due to one or more of the following reasons:

A sudden increase in sending volume, especially to Gmail addresses
Sending from a new or recently warmed IP
Campaigns sent to inactive or unengaged contacts
Workflow or automation sending emails too frequently
Higher-than-normal spam complaints or low engagement
Email authentication issues (SPF, DKIM, or DMARC misalignment)

Even legitimate senders can trigger this if email volume increases too quickly.

How to Fix This Issue

Step 1

Reduce sending volume to Gmail

Temporarily lower the number of emails sent to @gmail.com and @googlemail.com addresses.
Gradually increase volume over time instead of sending large bursts.

Step 2

Send only to engaged contacts

Focus on users who have recently opened or interacted with your emails.
Avoid sending to old, inactive, or purchased lists.

Step 3

Review automations and workflows

Check for workflows that may be sending emails repeatedly or too frequently.
Pause or adjust any campaigns that caused a sudden spike.

How Long Does Recovery Take?

In most cases, Gmail lifts the rate limit within 24–72 hours once sending behavior stabilizes. Continued good sending practices help restore normal delivery faster.

The Payoff

The 4.7.28 error is a temporary Gmail protection mechanism, not a permanent block. By slowing down email volume, sending to engaged users, and following Gmail's bulk sender best practices, email delivery will recover naturally.

Frequently Asked Questions

Q: Should I stop sending emails completely until this clears up?

Not necessarily. Pausing large campaigns and non-essential automations helps, but you don't need to stop all sending. Reducing volume and focusing on engaged contacts is usually enough to let Gmail lift the restriction.

Q: Does this error affect delivery to Outlook or Yahoo too?

No. The 4.7.28 error is specific to Gmail's own rate-limiting system. Other mailbox providers evaluate sending behavior independently and aren't affected by this particular restriction.

Q: What if I keep seeing this error after 72 hours?

If the error persists past 72 hours, revisit your sending volume, contact list quality, and authentication (SPF, DKIM, DMARC) again. A recurring error usually means the underlying cause hasn't fully been addressed.

Q: Will this permanently hurt my domain or IP reputation?

No, a single 4.7.28 event is not a lasting reputation hit. Repeated rate-limit triggers over time, however, can compound and slow down future deliverability, so it's worth addressing the root cause promptly.

Q: How do I know when sending volume is "safe" again?

Once you stop seeing the 4.7.28 error and your bounce and complaint rates return to normal, you can gradually ramp volume back up. Increase in small steps rather than jumping straight back to your previous send size.

Q: Is this the same as being added to a blacklist?

No. Blacklisting is a separate, more severe issue tracked by third-party reputation lists. This error is Gmail's own automated rate limiter and resolves on its own once sending behavior normalizes.