Forwarded emails to gmail are being rejected

I recently moved my domain to Cloudflare from Google Domains. However, mail emails are not being forwarded, with error messages like “421 4.3.0 Upstream error, please check Postmaster · Cloudflare Email Routing docs for possible reasons why. IzO1m3vlysEh”

Does anyone know how I can make email forwarding to my GMail address reliable?

Thank you kindly.


This is for the domain
Here is an example of a failed delivery.

[email protected]
[email protected]
21 hours ago
Delivery Failed
SPF status
DMARC status
DKIM status
Rejected reason:
Unknown error: transient error (421): 4.7.0 [ 19] Gmail has detected that this message is4.7.0 suspicious due to the very low reputation of the sending domain. To4.7.0 best protect our users from spam, the message has been blocked. For4.7.0 more information, go to4.7.0 n5-20020a252705000000b00dd17293ce62si4145593ybn.539 - gsmtp

Welcome to the Cloudflare Community. :logodrop:

The short answer is that you cannot make such forwarding reliable. It depends on too many elements over which you have no control.

When reliability is important, forwarding to a freemail provider is not going to meet the bill. Google email filtering is constantly adjusting its actions based on ever changing input. You can search the Community here and see this is a frequent occurance with a lengthy history. As long as there is still spam email to contend with, unpredictable temporary disruptions to email forwarding to Google are likely to occur.

For reliability, use MX routing, not forwarding to deliver your email.


Thank you! Exactly how would I set up MX routing to my GMail address? Thank you kindly.
My current MX records are:

You can’t. Gmail doesn’t support that without using a Google Workspace subscription.

The problem with forwarding to a free Gmail account is that they can decide not to accept the forwarded messages at any time without any notice for any reason. History indicates that this happens with enough regularity to generate recurring topics about it here in the Cloudflare Community.

To use MX routing you need a mailbox on a server that is configured to accept mail for your domain. If you really want to view that mail using your Gmail, you can add the account through Gmail settings. That approach also has the benefit of allowing you use that same external server to send mail using your domain email address, which is a function not available with forwarding.

You may want to peruse some of the recent similarly themed topics here in Email Routing to see if any of the approaches that others are taking will suit your needs.

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Thank you. That is what I used to do until a few years ago, hosting my email on a Hostrocket server and then using POP/IMAP from GMail to read it. It seems like time to revert to that setup. I guess things worked well for a while because before I was using Google Domains.




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