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Delivery Delays to Gmail

In the past 48 hours Google has started delaying the delivery of some FeedMail notifications. This is currently affecting about 10% of messages to Gmail users. These notifications will be resent with a delay. We also speculate that some notifications will be marked as spam.

 Update: As of 2023-05-09 this appears to be resolved.

If You Are Affected

If you use Gmail you may be affected by this. Notifications may be delayed or marked as spam.

  • If your notifications are marked as spam you can create a filter to avoid this. Use "from:*" as the rule and select "

More Details

The temporary rejection we are seeing from Google is in the form of:

transient error (421): 4.7.28 [ 15] Our system has detected an unusual rate of
4.7.28 unsolicited mail originating from your IP address. To protect our
4.7.28 users from spam, mail sent from your IP address has been temporarily
4.7.28 rate limited. Please visit
4.7.28 to
4.7.28 review our Bulk Email Senders Guidelines.

FeedMail does not send unsolicited mail so this is a false positive. However it is possible that it was triggered by a user marking FeedMail notifications as spam instead of unsubscribing which lead Google to believe that these messages were unsolicited.

Our email sending rate to Google users has not changed notably in the past couple of weeks so it is surprising to see this error occur.

We have submitted a Sender Contact Form but it does not suggest that we should expect a response.


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