Why is Gmail rate limiting my marketing and transactional emails after a period of low sending volume?
Michael Ko
Co-founder & CEO, Suped
Published 12 Aug 2025
Updated 27 May 2026
9 min read
Summarize with
Gmail is rate limiting your marketing and transactional emails because your recent sending pattern no longer matches the volume you are trying to send. A domain or IP that sends very little for several weeks can lose its recent Gmail baseline. When it suddenly sends a large campaign, Gmail treats that traffic as unusual and slows acceptance with temporary 4xx deferrals.
The most useful clue is the exact Gmail response. If the bounce says 4.7.28 and mentions an unusual rate of mail from your SPF domain, this is a temporary Gmail rate limit tied to the return-path or SPF domain Gmail sees. It is not the same as a permanent rejection, even when your ESP reports it as a bounce after retry time expires.
Marketing and transactional streams are not perfectly isolated just because one uses a subdomain and the other uses the root domain. Gmail can connect reputation signals across the visible From domain, return-path domain, DKIM domain, IPs, links, complaint patterns, and recipient engagement. Start with the domain named in the Gmail response, then check whether the transactional stream shares any of those identifiers.
The direct answer
A long quiet period lowers Gmail's expectation of how much mail your domain or IP will send. If you usually send small journey traffic and then send a large marketing batch, Gmail sees a volume spike. The spike can be enough to rate limit the SPF domain used in your bounce path, even if the domain has existed for years and previous campaigns performed well.
What the Gmail response means
This wording points to a rate limit rather than a normal mailbox-level bounce. Gmail is telling you which authenticated sending identity triggered the throttle.
- Status: A 4xx code means defer and retry, not permanently fail.
- Scope: The SPF domain in the response is the first identity to investigate.
- Cause: Recent low volume followed by a large campaign is a common trigger.
- Risk: ESP retry windows can expire and convert deferrals into reported bounces.
Typical Gmail 4.7.28 response
4.7.28 Gmail has detected an unusual rate of mail originating from your SPF domain [bounce.email.brand.co.uk]. To protect users from spam, mail sent from your domain has been temporarily rate limited. Review Gmail bulk sender guidance.
The confusing part is that your ESP can label the outcome as technical, unknown, or even bounced. That usually happens after the message sits in retry for hours and the sending platform gives up. The first diagnostic job is to separate the SMTP response from the ESP's reporting category.
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|---|---|---|
4.7.28 | Temporary rate limit | Slow Gmail volume |
4.4.7 | Retry window expired | Inspect prior deferrals |
SPF domain | Return-path reputation | Map sender sources |
Root domain | Shared trust signal | Check every stream |
How to read common Gmail evidence.
Why low volume causes a sudden Gmail throttle
Gmail does not only care that you sent a similar campaign two months ago. It cares about recent, expected behavior. A domain that sends a few journey emails for six weeks and then sends hundreds of thousands of marketing emails has changed behavior in the period Gmail uses to judge risk.
That is why a campaign can go from 99.5% delivery to a large Gmail failure rate without an obvious DNS change. The change was the sending rhythm. A quiet period lets IP and domain reputation cool. The next high-volume send asks Gmail to accept more mail than the sender's recent track record supports.
Sending gap risk
A practical way to think about how much recent Gmail volume you need before a large send.
Normal
0-7 days
Regular sends with no long quiet gap
Caution
8-21 days
Recent baseline starts to thin out
Rewarm
22+ days
Treat large Gmail volume as risky
The longer the quiet gap, the more conservative the next Gmail send should be. If you send one major campaign every other month, the safe pattern is not to wait and blast. Keep a small, engaged Gmail segment moving between large sends, or treat each major campaign like a partial rewarm.
What Gmail sees
- Volume: A sharp jump against recent Gmail traffic.
- Identity: Return-path, DKIM, From domain, IP, and links.
- Behavior: Opens, complaints, spam placement, and inactive recipients.
- History: Recent signals carry more practical weight than old wins.
What senders often see
- Reports: Unknown or technical bounces after retries expire.
- Confusion: Marketing failure followed by transactional delays.
- Assumption: Similar campaign size means similar Gmail treatment.
- Fix: Rebuild steady volume before the next large batch.
What to check first
I start with evidence, not assumptions. Get the full unedited SMTP response for both the marketing platform and the transactional platform. In Marketing Cloud, the bounce data view is often the fastest place to pull the unredacted message. For SendGrid or any transactional sender, pull the raw event reason and SMTP response, not only the dashboard category.
- Bounce text: Confirm whether Gmail returned 4.7.28, 4.4.7, or another code.
- SPF domain: Identify the return-path domain named in Gmail's response.
- Volume graph: Compare the last 30 to 60 days against the failing campaign day.
- Gmail split: Segment Gmail addresses separately from the rest of the list.
- Authentication: Run a domain health check before sending again.
Google Postmaster Tools dashboard showing reputation and delivery errors.
Google Postmaster Tools can help when the root domain has enough Gmail volume to show data. Look at domain reputation, IP reputation, spam rate, authentication, and delivery errors around the campaign date. If the tool shows low reputation or a delivery error spike, treat the next send as a recovery send, not a normal campaign.
Do not confuse this with outbound mailbox sending caps such as Workspace limits. Those limits control how much mail a Google Workspace account can send. The issue here is Gmail deciding how much inbound mail it will accept from your sending identity.
Email tester
Send a real email to this address. Suped opens the report when the test is ready.
?/43tests passed
Preparing test address...
Before resuming volume, send a real message through the same platform, bounce domain, DKIM selector, and From domain you plan to use. A live email tester run will not prove Gmail reputation is fixed, but it catches broken authentication, bad headers, and content issues before you add volume.
How marketing can affect transactional mail
Transactional mail can be affected after a marketing spike when the streams share reputation signals. A different platform does not guarantee isolation. If the marketing stream uses email.brand.co.uk and the transactional stream uses brand.co.uk, Gmail can still associate the traffic through the organizational domain, DKIM d= domain, bounce domain, link domains, and recipient response.
The practical question is not whether isolation exists in theory. The question is which identifiers overlap. I map each stream in a small matrix and mark every shared item. The more overlap, the more likely a Gmail rate limit on one stream creates drag on the other.
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|---|---|---|
From | email subdomain | root domain |
Bounce | marketing bounce | transactional bounce |
DKIM | platform selector | app selector |
Links | tracking host | app host |
IPs | bulk pool | transactional pool |
Isolation checks for marketing and transactional streams.
If the transactional sender has different bounce domains, DKIM selectors, and IPs, it has stronger separation. If it shares the same root-domain reputation, branded link host, or sending IP pool, isolation is weaker. The SendGrid bounces matter because they show whether Gmail named the same SPF domain or a related identity.
Flowchart for diagnosing Gmail rate limiting after low sending volume.
A practical recovery plan
The fix is to reduce Gmail volume, rebuild recent reputation, and keep transactionals protected while the marketing stream recovers. Do not resend the failed campaign to the same Gmail audience at full size. That repeats the pattern Gmail just throttled.
- Pause: Stop large Gmail batches until deferrals fall back to normal.
- Segment: Send first to recently engaged Gmail recipients only.
- Ramp: Increase Gmail volume in controlled steps over several sends.
- Separate: Keep transactional mail on its own authenticated path.
- Monitor: Watch Gmail deferrals, spam rate, complaints, and DMARC failures.
Example Gmail recovery ramp
Use percentages of the normal Gmail campaign size, then adjust based on deferrals and engagement.
Gmail volume
A recovery ramp is not a fixed daily schedule. It is a decision loop. If Gmail deferrals rise, hold or step back. If Gmail accepts the mail and engaged users interact normally, increase. For a deeper recovery model, use a ramp-up strategy based on engagement tiers, not a flat percentage of the whole list.
Do not retry the whole failed audience
A full resend to Gmail after a 4.7.28 event usually extends the problem. Gmail has already told you the rate is unusual.
- Better: Start with recent openers, clickers, buyers, or active app users.
- Hold: Suppress inactive Gmail recipients until reputation recovers.
- Protect: Keep password resets, receipts, and account alerts separate.
If you are also seeing 421 4.7.28 deferrals, treat them as the same family of symptoms: Gmail is slowing acceptance because the traffic profile looks risky.
Where Suped fits
Suped is the strongest practical DMARC platform for this workflow because the problem crosses DMARC, SPF, DKIM, reputation, and operational alerting. The fix is not only to publish correct DNS. You need to see which sources are authenticated, which sources fail, and when Gmail-related failure rates change.
Issues page showing top issues, verified sources, unverified sources, and authentication pass rates
In Suped, I use DMARC monitoring to confirm that every marketing and transactional source is passing authentication. Then I watch source-level failures, unverified senders, and sudden shifts in authentication health. That narrows the question from "Gmail hates us" to "this bounce domain, source, or selector changed behavior."
Suped's product also brings Hosted SPF, SPF flattening, Hosted DMARC, Hosted MTA-STS, real-time alerts, and blocklist (blacklist) visibility into one place. The blocklist monitoring view is useful when a Gmail issue happens alongside wider IP or domain reputation concerns. A blocklist or blacklist entry is not the usual cause of a Gmail 4.7.28 rate limit, but it belongs in the same incident checklist.
Manual incident handling
- Collection: Pull bounce logs, DNS records, source lists, and Postmaster data.
- Analysis: Compare each platform's SPF, DKIM, and DMARC behavior.
- Risk: Missed source changes delay recovery and protect fewer streams.
Suped workflow
- Detection: Automated issue detection flags authentication and source problems.
- Action: Steps to fix help teams correct DNS and sender setup quickly.
- Scale: MSP and multi-tenant views help manage many domains at once.
Views from the trenches
Best practices
Keep low, steady Gmail volume between campaigns so reputation does not cool off for weeks.
Pull full SMTP responses before diagnosing bounces reported by marketing or app platforms.
Map every shared sender identity before assuming subdomains isolate reputation completely.
Common pitfalls
Treating a 4xx Gmail deferral as a hard bounce hides the real temporary rate limit.
Sending one large campaign after six quiet weeks can exceed Gmail's recent expectation.
Ignoring transactional bounce logs leaves shared domain reputation questions unresolved.
Expert tips
Use engaged Gmail recipients first, then expand volume only when deferrals stay normal.
Check Google Postmaster Tools on the root domain when Gmail volume is high enough.
Keep critical transactional traffic on separate bounce, DKIM, and IP infrastructure.
Marketer from Email Geeks says the full Gmail bounce message is the first evidence to collect because categories alone hide whether the event was a deferral or a permanent rejection.
2025-02-04 - Email Geeks
Marketer from Email Geeks says a 4.7.28 response usually points to temporary Gmail rate limiting, and the named SPF domain should drive the first investigation.
2025-02-04 - Email Geeks
The practical fix
When Gmail says your SPF domain is sending at an unusual rate, accept that diagnosis and slow down. The sender is not always new, the campaign can look similar to an older campaign, and authentication can pass. Gmail is still reacting to the recent sending baseline.
The recovery path is clear: collect the full bounce messages, map the identities across marketing and transactional streams, check domain and IP reputation, reduce Gmail volume, and rebuild with engaged recipients. Keep a maintenance stream between major campaigns so Gmail does not see the next send as a sudden return from silence.
Suped's role is to keep the authentication and reputation side visible while you recover. When DMARC, SPF, DKIM, sender sources, hosted SPF, MTA-STS, alerts, and blocklist or blacklist checks are in one workflow, the team spends less time guessing and more time fixing the stream that actually changed.
