topic Re: Problems sending to gmail in Email

Problems sending to gmail

abitpedantic — Fri, 27 Mar 2026 10:21:05 GMT

My emails to gmail addresses are currently being rejected. After 70 - 90 minutes I get an NDR saying:

"Gmail has detected an unusual rate of mail originating from your SPF 421-4.7.28 domain" and "To protect our users from 421-4.7.28 spam, mail sent from your domain has been temporarily rate limited".

I don’t know why this has happened and the rate has been limited to zero!

Is anyone familiar with this issue and can explain it?

How long is “temporarily” (it's already been like this for two days) and is there anything I can do about it?

Re: Problems sending to gmail

jab1 — Fri, 27 Mar 2026 10:32:46 GMT

@abitpedantic I suspect this is gMails latest attempt to disrupt PN - and possibly others messages. Remember the fiasco last year - and ongoing - with M$ and gMail?

Re: Problems sending to gmail

abitpedantic — Fri, 27 Mar 2026 10:52:14 GMT

I do remember it but I did a search and didn't find this particular reason being given before. Is it actually blaming my specific account? If not, I'm surprised that others have not reported the issue before.

I should clarify that I'm sending from self@account.plus.com.

Re: Problems sending to gmail

jab1 — Fri, 27 Mar 2026 10:53:17 GMT

Reading that response '"Gmail has detected an unusual rate of mail originating from your SPF 421-4.7.28 domain" and "To protect our users from 421-4.7.28 spam, mail sent from your domain has been temporarily rate limited".' , I am tempted to think they are trying to lump all PN accounts into one again, but I haven't examined what '421-4.7.28 spam' is supposed to be, and I don't have the time just now.

Re: Problems sending to gmail

pvmb — Fri, 27 Mar 2026 11:08:26 GMT

Perhaps it depends on what exactly "domain" means here?

I do not have and have never had my own hosted domain, however is not @<Plusnet user>.plus.com considered to be a "domain"? So every PN email user account might be a domain to Gmail. In which case the issue could well be with the particular user account (via account hacking or spoofing) rather than a Plusnet or Greenby problem.

For me the question remains: Why are some people suffering from all these various problems while others are not?

Re: Problems sending to gmail

abitpedantic — Fri, 27 Mar 2026 11:36:36 GMT

I did try to post the full NDR on this forum but ironically my post was suppressed as spam!

The NDR actually says “Gmail has detected an unusual rate of mail originating from your SPF 421-4.7.28 domain [******.plus.com 35]”.

so perhaps there is a hacking/spoofing issue which I will find out more about as time goes on. Or maybe I’m just being given special treatment “temporarily”.

Re: Problems sending to gmail

jab1 — Fri, 27 Mar 2026 11:55:01 GMT

@abitpedantic But you are not sending from a domain, you are sending from an individual, private address - as said previously this is Google playing sill moo's again.

Re: Problems sending to gmail

MisterW — Fri, 27 Mar 2026 13:31:42 GMT

For information, I've made the relevant people aware of this issue

Re: Problems sending to gmail

PhilipHeyes — Fri, 27 Mar 2026 13:49:19 GMT

Today I manually created and sent a email via Plusnet's SMTP server relay.plus.net using it as an Open Relay
( i.e. no Credentials supplied ) from our Virgin Media internet connection.

This should not work, but it did and the email was delivered seconds later.

A spam senders dream.

Re: Problems sending to gmail

jab1 — Fri, 27 Mar 2026 13:57:51 GMT

Out of interest, @PhilipHeyes , what is the relevance of that - IF you have read the original post?

Re: Problems sending to gmail

PhilipHeyes — Fri, 27 Mar 2026 14:11:04 GMT

Could an earlier burst of emails from a spam sender using a hijacked xxxx@yyyy.plus.com email address
have triggered Gmail's attention as the too much traffic from domain "plus.com" ?

Re: Problems sending to gmail

jab1 — Fri, 27 Mar 2026 14:14:08 GMT

Possible, I suppose. We will have to see if anyone else reports the same rejection message.

Re: Problems sending to gmail

abitpedantic — Fri, 27 Mar 2026 15:04:57 GMT

@MisterW

Thank you. Can I expect one of the "relevant people" to get back to me explaining what is going on? Soon?

Re: Problems sending to gmail

MisterW — Fri, 27 Mar 2026 15:13:36 GMT

I really don't know. It may take a while to understand what gmail is complaining about. That may need conversations with gmail and that may not be quick...

Re: Problems sending to gmail

pvmb — Fri, 27 Mar 2026 15:25:39 GMT

@jab1 wrote:

@abitpedantic But you are not sending from a domain, you are sending from an individual, private address

Which, surely, is inherently and unavoidably coming from some "domain"?

Re: Problems sending to gmail

abitpedantic — Sat, 28 Mar 2026 18:12:11 GMT

This morning I sent a test message from self@account.plus.com to us@gmail.com and it was delivered almost immediately.

I then sent the same message from wife@account.plus.com to us@gmail.com. 70 minutes later an NDR, just like before, was received. And again a couple of hours later. So, effectively hopeless.

Given that quite a high percentage of people seem to be on gmail, unless this can be resolved, I can see it being the end of our long association with Plusnet email.

Re: Problems sending to gmail

abitpedantic — Sun, 29 Mar 2026 21:53:54 GMT

@MisterW

Today's test was an email from wife@account.plus.com to us@gmail.com.

It was sent at 16.07. It is now 22.50 and there has been no delivery and no NDR (and yes, I've looked in her Spam folder).

It has been 4 days since gmail first took umbrage at our Plusnet emails. Clearly, "temporarily rate limited" seems to be heading towards "permanently completely discarded".

I'd be grateful if you could let the "relevant people" know about this latest deterioration.

Thank you.

Re: Problems sending to gmail

Chris_S — Tue, 31 Mar 2026 07:54:36 GMT

Hi @abitpedantic

Thanks for highlighting this issue to us.

If you're still experiencing this issue this morning, could you check your email headers and send over the information please?

If there's any personal infomation in the headers, please send me over a Private message.

You can find information on how to find the infomation on our email headers help page.

Chris S

Re: Problems sending to gmail

MisterW — Tue, 31 Mar 2026 08:11:33 GMT

@Chris_S

I can confirm its still happening. A test message to my gmail account yesterday has still not been delivered and no NDR. Test message this morning looks to the same. A message from my externally hosted domain to my gmail account is delivered instantly!

I've already added my comments to the gmail problems thread in the SU space

Re: Problems sending to gmail

Chris_S — Tue, 31 Mar 2026 09:11:25 GMT

Hi @MisterW

Thanks for your feedback.

We're sending examples to our support team to get them reviewed.

If you haven't sent an example to us yourself yet, I'd be happy to send that over for you.

Chris S