SMTP error 452

[#1]

I understand the logic, but it it is possible I think the name of this thread needs amplifying so that people searching for a reference to their email problem have a chance of finding it.

[#2]

Cannot send emails, either from PC or iPhone covers a multitude of diverse and colourful sins, arising from various causes.

SMTP error 452 is a very clear description pointing to a specific issue giving clear direction to the likely cause.

[#3]

I posted elsewhere this morning re the errors on sending with my PC and iPhone: I'm pleased to say the email now sends and receives as usual. Thank you everyone who had input and then escalated the issue - seems to have done the trick!

[#4]

17:45 The issue is still extent.  It will be seen periodically as the limiting quota is reset on the hour.

[#5]

Ive just spoken to Plusnet support 🙂

I very kind and helpful lady explained in simple terms that this and other problems are due to some server work associated with the upcoming migration of our email accounts to the new provider. 

It may be more or less complicated than that, but that is the crux of it.

They know about it and are working on it 🙂 

We will all get two emails - one at 60 days and one at 30 days before our full transfer to the new provider.

I personally think we may expect more issues as the migration progresses, but hope Im wrong 😉

[#6]

@Townman 

I had this problem on Thursday at 20.33 but successfully resent the email at 23.25 after most sensible people had gone to bed!

Is it possible that Plusnet are fiddling with things in an effort to solve other problems, such as the long-standing issue of everyone being treated as a spammer by Hotmail and Outlook servers?

[#7]

@Townman

I first had this issue last night. when sendsing from my usrname@acount.plus.com address.

The problem then cleared, but the same issue returned this morning.

This was the error message.

Sent:    14/09/2025 11:48

The following recipient(s) cannot be reached:

      'xxxxxxxxx@googlemail.com' on 14/09/2025 11:48

            Server error: '452 <xxxxxxxxx@googlemail.com> recipient rejected - too many recipients in last hour'

I have only been sending handful of emails, each one to only one or two recipients.

Nol multiple

I am not off network and I am connected via my home Plusnet router..

Can @Townman or any other well informed PN superusers/friends please summarise the latest state of play for me?

With the best will in the world, one wonders how much worse the Plunset email service can get in the run-up to migration.

It's a mess.

[#8]

Me too!

I don't send many emails and only found out about this problem within the last few minutes. I am also prevented by sending emails due to this "too many recipients in the last hour" error.

Peter

[#9]

@Baldrick1 I disagree. A terse, cryptic subject like SMTP error 452 will not be understood by the vast majority of people looking for help on this ongoing fault. This smacks of trying to hide something.

Some email clients present with the explanation "too many recipients" and this has spun off "nugatory" distracting discussions about quotas and the like. The error is presented by the server due to email server RESOURCE EXHAUSTION - memory, storage, volume.

Please consider re-titling so that more will find this thread?

[#10]

I have the same problems.

I am currently dealing with my fathers probate and in the selling of his flat.

I need a reliable email service as tis is creating inordinate stress and delays in communications.

I don't know what Plusnet have done but it really is just unacceptable - but as we know we have to accept it along with all the other issues with Plusnet email.

This is the error sent from my self to my wife on the same plusnet domain :

Your message did not reach some or all of the intended recipients.

      Subject:     test

      Sent: 14/09/2025 13:55

The following recipient(s) cannot be reached:

      janette (xxxxx@xxxxx.plus.com) on 14/09/2025 13:55

            Server error: ’452 <xxxxx@xxxxx.plus.com> recipient rejected - too many recipient in last hour’

Plusnet can't even manage emails within it's own infrastructure - what's going on and when will it be fixed?

[#11]

@JaAm This fiasco is linked to the impenidng move of the email service, but unfortunately it, and the issues it is causing, have come at an unfortunate moment as PN are still trying to resolve the Microsoft and Gmail imposed problems.

One would hope that someone at management level would be constructing an informative response as we speak, but that is rather like hoping you have won the Lottery - when you haven't even entered.

[#12]

---

@disfroot wrote:

@Baldrick1 I disagree. A terse, cryptic subject like SMTP error 452 will not be understood by the vast majority of people looking for help on this ongoing fault. This smacks of trying to hide something.

---

There's no intention of hiding anything, there's every intention to eliminate a scatter gun approach that helps no-one. I have amended the title to clarify the subject matter.

[#13]

@abitpedantic 

No this is not consequential to fiddling to fix other things; I suspect that it is a complication of the service migration activity, precise cause not known to me, though I have theories.

@PeterB1 

In short as one of several planks in the email service's anti-abuse measures is a volume submission limitation - there is a limit to the number of email addressees which can be submitted per hour from a specific scope.  The nature of that scope is (correctly) not known to users.  Historically we have seen this profile of operational issue where users are hiding behind a VPN proxy to use (exploit?) the email service.  Thereby one sees a volume limitation across numerous individual users accessing the mail service through the same VPN.

The volume metric is different for UK deemed and overseas deemed IP addresses.

If I had to guess, it would be that the pre-migration move of the *.plus.net servers to the Greenby proxy might have some bearing on the experience.

The characteristic of this volume limiting control is that when the quota is used, no more email nay be sent within the quarantine period.  The quota / quarantine period is reset on the hour, thereby one perceives a working, no its not, yes it is experience.

@disfroot - your "terse, cryptic" is in fact a concise accurate articulation of what folks see on most proper email clients which report back exactly what is happening, rather than the terse and cryptic "something went wrong" or just "failed to send" messages given by those email clients which seek to hide what is really happening.

You are though now better informed about the situation, which is more than what your email client did for you.

[#14]

Thanks for the update and the theories, @Townman .

I think you're aware oif this, but just t be clear: I am not using a VPN and I'm in the UK, not poverseas - as I think are most if not all the other customers who've been posting about Error 452. As for the migration, I doubt if I'm alone in suspecting the process will be a nightmare with multiple users quickly giving up and depriving Plusnet of whatever income  the company is expecting from Greenby for the new customer base.

In the shorf term, if this latest mess is indeed connected with the migration, I'm sure most customers would want the move to the move of servers to the Greenby proxy to be reversed and the service stabilised until a way can be found to manage the transition without this sort of mayhem.

With best wishes and thanks for your helpful responses as always

[#15]

Happening here this week, and the problem seems to go once the clock ticks past the hour. 

This is very frustrating.