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Cannot send emails, either from PC or iPhone

Richiebee
Hooked
Posts: 7
Thanks: 2
Fixes: 1
Registered: ‎23-08-2025

Cannot send emails, either from PC or iPhone

‎13-09-2025 2:06 PM

Beginning today, I am unable to send an email from either my PC/Win10/Thunderbird, or iPhone/email. I am sending test emails to myself with the following results (the error messages are different):

PC: 'Sending of the message failed. An error occurred while sending mail. The mail server responded: <email address> recipient rejected - too many recipient in last hour. Please check the message recipient "email address" and try again.'

iPhone: 'Cannot Send Mail. "email address" is not a valid email address and has been rejected by the server. The message has been placed in your outbox.'

I appear to be receiving emails in OK. I haven't altered any settings.

I've seen the PC error message elsewhere on this forum (some time ago) but the iPhone message is eye-opening. Does anyone else have experience of this, or is it just me? All and any help gratefully received.

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JudithPS77
Hooked
Posts: 8
Thanks: 5
Registered: ‎29-10-2021

Re: Cannot send emails, either from PC or iPhone

‎13-09-2025 2:45 PM

The same thing has happened to us.  First message was to a hotmail account, rejected yesterday, so I thought it was part of the ongoing (months old) problem with Microsoft on this thread https://community.plus.net/t5/Email/From-address-doesn-t-meet-the-authentication-requirements/m-p/20...

But today we cannot send anything to anyone, including our own variants on our webmail addresses. Emails have a single recipient, sometimes ourselves, with a variety of providers including plusnet, gmail and hotmail.  We have tried on different computers using Thunderbird and via webmail.  We use plusnet broadband so are connected via plusnet servers.  Today nothing will send - we always get this same message

"Sending of the message failed.

An error occurred while sending mail. The mail server responded: 

<....@gmail.com> recipient rejected - too many recipient in last hour.

 Please check the message recipient "...@gmail.com" and try again."

What on earth is going on?

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cmon_mary
Grafter
Posts: 27
Thanks: 13
Registered: ‎06-09-2019

Re: Cannot send emails, either from PC or iPhone

‎13-09-2025 2:56 PM

Same issue - system does not recognise the Plusnet email address I am sending from or the Plusnet address I am sending to.

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Townman
Superuser
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Posts: 28,185
Thanks: 12,601
Fixes: 236
Registered: ‎22-08-2007

Re: Cannot send emails, either from PC or iPhone

‎13-09-2025 3:07 PM

See https://community.plus.net/t5/Email/SMTP-error-452/td-p/2017606/jump-to/first-unread-message

In another browser tab, login into the Plusnet user portal BEFORE clicking the fault & ticket links

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

If this post helped, please click the Thumbs Up and if it fixed your issue, please click the This fixed my problem green button below.

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Baldrick1
Moderator
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Posts: 13,695
Thanks: 6,679
Fixes: 459
Registered: ‎30-06-2016

Re: Cannot send emails, either from PC or iPhone

‎13-09-2025 3:35 PM

Topic locked in favour of https://community.plus.net/t5/Email/SMTP-error-452/m-p/2017606#M51937

Moderator and Customer
If this helped - select the Thumb
If it fixed it,  help others - select 'This Fixed My Problem'

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