From address doesn't meet the authentication requirements defined for the sender

[#1]

It works with hotmail, not tried with the others. I had gone to the Yahoo web site and opened an account years ago, as a kind of backup really which I have rarely used. To do that you have to create a password. That is the password that I used for the Yahoo STMP server. In kmail multiple servers can exist side by side, so Plusnet is the default but I can select a different one.

[#2]

It’s possible to have multiple accounts in mist email clients, each with their own email address, using their respective SMTP servers.

The key piece of information required here is are you send from your Plusnet email address through the yahoo SMTP servers.

Are you sure that you’re not sending using your Yahoo email address with a on behalf of the Plusnet address?

[#3]

Hmm, I don't know. I simply put the Yahoo email details in the boxes to configure the sender and sent it. There are boxes for a custom hostname and a custom sender address but I left them blank. I got a reply this morning from a friend on hotmail so something is working, but now I have my doubts over this because I just tried sending a message to myself using the Yahoo sender and it won't go. Can't do any more just now.

[#4]

Any news on a possible fix?  Is PN in discussions with MS?

While I appreciate the frustration with MS, I don't think just saying "they shouldn't have done that" gets us very far.

[#5]

@Tim-J - What should they do then? It  is MS (and Gmail) not behaving nicely.

[#6]

@jab1 'they', as in Plusnet, the company from which we, paying customers, are NOT receiving a worthwhile email service, should stop griping and do what they have to do reinstate a worthwhile email service.

If they don't, I for one, will not spend any more money with Plusnet.

[#7]

@stuck The email service is a 'free' add-on - many ISPs don't offer one at all.

[#8]

While it is MS causing the problem, it is not going to be solved if Plusnet just sit back and say "nothing to do with us".  I asked if they were in discussion with MS to try to get a resolution.  They are in a better position to do that than ordinary users like you or me.

[#9]

Sorry I think I must have got my messages or the failure messages mixed up when I thought one went via Yahoo - apologies for sending you down a blind alley. One had gone though, and I have just sent another which has not been rejected but I'm not clear what settings are needed.

However there is a web site, https://www.learndmarc.com/, which gives you an address to send a message to and it runs a diagnosis. So the thing I could do is try it with different settings in the sender, although I don't really understand these three flags. Here is the output I got the first time:

DMARC Results

--- Connection parameters ---
Source IP address: 84.93.230.235
Hostname: avasout-ptp-002.plus.net
Sender: [Removed]

--- SPF ---
Domain: [Removed]
Identity: RFC5321.MailFrom
Auth Result: none
DMARC Alignment: n/a

--- DKIM ---
Domain: plus.com
Selector: 042019
Algorithm: rsa-sha256 (2048-bit)
Auth Result: PASS
DMARC Alignment: PASS

--- DMARC ---
Warning: No DMARC record found – this can severely impact your email deliverability and harm your domain’s reputation!

RFC5322.From domain: [Removed]
Policy (p=): reject (simulated)
SPF: FAIL
DKIM: PASS
DMARC Result: PASS

--- Final verdict ---
DMARC does not take any specific action regarding message delivery. Generally, this means that the message will be successfully delivered. However, it's important to note that other factors like spam filters can still reject or quarantine a message.

Moderator's note by Mike (Mav): Personal information removed from a public forum (to an area that staff can see).

[#10]

Thanks Richard_R for https://www.learndmarc.com/. I just tried it out with my email.
Everything that came from that site matched yours (apart from being different users etc.).
The output:

DMARC Results
Connection parameters
Source IP address 212.159.14.20
Hostname avasout-peh-004.plus.net
Sender [Removed]
SPF
Domain [Removed]
Identity RFC5321.MailFrom
Auth Result none
DMARC Alignment n/a
DKIM
Domain plus.com
Selector 042019 
Algorithm rsa-sha256 (2048-bit)
Auth Result PASS
DMARC Alignment PASS
DMARC
Warning: No DMARC record found – this can severely impact your email deliverability and harm your domain’s reputation!
RFC5322.From domain [Removed]🔍
Policy (p=) reject (simulated)
SPF FAIL
DKIM PASS
DMARC Result PASS
Final verdict:

DMARC does not take any specific action regarding message delivery. Generally, this means that the message will be successfully delivered. However, it's important to note that other factors like spam filters can still reject or quarantine a message.

I immediately tried to email to a hotmail account and it bounced with :

550 5.7.515 Access denied, sending domain ERICPARKER.PLUS.COM doesn't meet the required authentication level.

Moderator's note by Mike (Mav): Personal information removed from a public forum (to an area that staff can see).

[#11]

An interesting development.

Some time ago, I set up two auto-forwards via my Plusnet email account, of posts received from a small society mailing list.  This was at the request of two society members who had been having intermittent problems receiving them direct.  One has an Outlook address, the other Hotmail.

Last week, both of these auto-forwards were bouncing immediately, just like anything else sent to Outlook or Hotmail.

A short while ago this evening (Monday) I got a bounce message for one to Hotmail, but not for the corresponding one to Outlook.

Two possibilities: either Outlook have re-started delivering them, or they have stopped sending bounce messages for them.  (I can't easily ask my contacts which it is; they probably haven't even noticed there has been a problem.)

If it's the former and Outlook have indeed re-started delivering as a result of requests from PN, then thank you to the PN team, and let's hope Hotmail and other Outlook proxies will follow.

[#12]

I'm getting exactly the same: did a group reply to 30ish emails including Gmail; Hotmail.com & .co.uk and it was only the Hotmail ones which bounced

[#13]

Same problem here sending from both PC and mobile phone. However, I went out this morning, tried replying to an email from a hotmail address and it sent (I was using the EE mobile network) got home, tried the same thing to the same email address from home .... and it bounced again (at home it sends via plus.net broadband). I have no idea what is going on

[#14]

This thread explains exactly what is going on - Microsoft is playing hard ball changing the rules for email communications.

[#15]

When you're connecting via EE you get assigned a separate IP address, so it probs looks ok to Hotmail.

I usually get the opposite, connecting via O2 Plusnet mainly rejects my emails since a lot of O2 IP,s must be used for spam so are black listed 😞