topic Re: From address doesn't meet the authentication requirements defined for the sender in Email

e-mail delivery issues

ebforum — Fri, 24 Oct 2025 07:45:51 GMT

During the 23 October I have experienced long delays with e-mails from several sources, including PayPal. One e-mail was sent at 15:24 but wasn't received in my Outlook 365 e-mail client app (on my Windows PC) until 21:23. Strangely, other e-mails arrived in a timely manner.

With the help of an IT-skilled friend who examined my e-mail headers, it appears that e-mails are going through an e-mail server with the name of called email.co. Interestingly, this server is owned by Enix Ltd who offer Greenby e-mail. It is therefore reasonable to assume that as part of the e-mail migration to Greenby, the normal route of e-mails into Plusnet's domain is fronted by this server.

I attach a screen shot of my Plusnet webmail inbox date column which shows the time delays very effectively, which also corresponds with the delays in Outlook 365 on my PC.

Is this Enix/Greenby server introducing these delays for some reason? The results that are seen in my Plusnet webmail and Outlook 365 cannot be disputed.

Does the Enix/Greenby server "sit in front" of Plusnet's webmail server and the servers I connect to for Outlook 365, thereby introducing the same delay to both server environments?

@plusnettony can you assist please?

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

ebforum — Thu, 23 Oct 2025 19:43:40 GMT

As of today, I am receiving, into my Outlook 365 Inbox, several e-mails out of sequence from when they were sent. Is it possible that the changes applied could be making this happen?

They are from several sources including PayPal.

Thanks.

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

Townman — Thu, 23 Oct 2025 19:58:50 GMT

They could well be sorted by date / time received.

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

ebforum — Thu, 23 Oct 2025 20:05:34 GMT

Nothing has changed in how my Inbox is sorted. It seems that there is like a delay in some being "processed by Plusnet" as Plusnet webmail is showing the same out of sequence situation.

Very strange.

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

Townman — Thu, 23 Oct 2025 20:18:07 GMT

Back to your question.

This is unlikely to be due to anything at Plusnet’s end; in respect of Microsoft’s problems, nothing has been changed in Plusnet’s world, so anything time coincidentally different is down to Microsoft.

Though Plusnet’s systems might have processed the email in a timely fashion, without access to the outbound servers, there’s no assurance that when sent successfully that was the first attempt, previous attempts failing due to Microsoft’s refusal to accept. This is known as grey listing (as seen with Gmail) or could indicate the Microsoft’s systems are overloaded.

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

ebforum — Thu, 23 Oct 2025 20:23:37 GMT

What surprised me is that three e-mails from PayPal arrived completely out of sequence to the time of the transaction.

Oh well

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

ebforum — Thu, 23 Oct 2025 20:31:14 GMT

Furthermore, an e-mail that was sent at 3:30pm today, has just arrived!

The e-mails concerned are from different domains.

Technology eh!

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

ebforum — Thu, 23 Oct 2025 21:36:25 GMT

I asked a highly skilled IT friend to look at the headers of one of my much delayed e-mails.

He identified that a server, within the chain of servers, called email.co is causing the delays I am experiencing. Interestingly, this server is owned by Enix Ltd who offer Greenby e-mail.

Therefore, it seems reasonable that the migration processes are underway with delays being introduced by an additional server that sits before the normal Plusnet servers.

Furthermore, on looking at my Plusnet webmail, the Inbox is very much out of sequence.

I realise that this thread is now not the right place for this problem but is there anyone here with a link back into the Plusnet technical team who can relay this nasty problem to them.

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

Townman — Thu, 23 Oct 2025 21:55:05 GMT

How does your friend reach that conclusion?

All that can be drawn for the headers is the ACCEPTANCE time of the servers in the chain (received from times). Where there’s a sizeable gap, it is NOT possible to discern the difference between a delay in the sending environment and the receiving environment declining acceptance of delivery attempts. The email headers do not indicate the first send attempt, just the delivery acceptance time.

This has the typical hallmark of issues related to Gmail accepting delivery. There are multiple examples around here of emails being sent from Plusnet to multiple addressees: non-Gmail addresses receive the email immediately - Gmail some hours later.

To discern the difference between a sending delay and a delivery acceptance delay requires access to the sending MX’s systems logs to determine if there were refused delivery attempts.

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

ebforum — Thu, 23 Oct 2025 22:17:10 GMT

With e-mails being sent to me from different sources, one being PayPal, surely it is possible to deduce that a common component in the chain of servers is causing the problem, that being the Greenby server which clearly wasn't in the chain before.

Also, why when logging on to Plusnet e-mail there is a message about the sort function being disabled? Could this be because there is an anticipated sorting issue?

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

Townman — Thu, 23 Oct 2025 22:24:04 GMT

Webmail sort function has nothing to with anything other than accessing the IMAP server.

Your previous post suggested issues receiving mail to your outlook account. Now you’re talking about receiving to a Plusnet account.

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

ebforum — Thu, 23 Oct 2025 22:49:54 GMT

I have no idea where you are seeing me mentioning an Outlook account? I referred earlier to my Outlook 365 inbox. Outlook 365 is my mail client, not my e-mail address.

I have not discussed anything other than my Plusnet e-mail which is accessed by Outlook 365 as part of my Office 365 suite.

As to webmail via the IMAP server, it has the same date and time stamp disarray as my Outlook 365 inbox. One e-mail shows a time of 15:35 today and arrival time in my Outlook inbox at 21:23.

Attached is a picture of the e-mails in Plusnet webmail inbox with the out of sequence times which matches my Outlook 365 Inbox. There are other e-mails in both inboxes that arrived in a timely manner. However, as said above, some of the very late arriving e-mails are from PayPal which surely must have some credibility.

Re: e-mail delivery issues

jab1 — Fri, 24 Oct 2025 07:51:56 GMT

@ebforum I too am noticing this 'delayed delivery' for the first time in memory, and analysis of the headers on the delayed messages indicates the culprit to be additional 'checks' by a source I have not seen before. I collect mail through 'MailWasher', which conveniently indicates the time sent and received.

Of the 3 sat on MW at the moment, one was sent at 1606 and received 2023, one sent at 1801 and received at 2024 (yesterday) and one sent at 0727 and received at 0753 (today).

Previously, all these messages would have the same times for both (to within a minute at times).

This is not not good, with the number of sites which are now requesting you enter an emailed validation code, which typically is only valid for 10 minutes.

Re: e-mail delivery issues

ebforum — Fri, 24 Oct 2025 07:58:03 GMT

@jab1 are the additional checks you mention carried out by the server I mentioned in my initial post?

I agree that this is a serious issue for many reasons, including the one you mention about validation codes.

What surprises me is that the delays do not affect all e-mails.

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

Townman — Fri, 24 Oct 2025 08:21:08 GMT

@ebforum

It helps no one if you piggy-backing a discussion about RECEIVING emails on a thread about SENDING emails to Outlook Inboxes.

I have asked the mods to split your posts off to somewhere else. I have received objective evidence for elsewhere which is being reviewed.

Re: e-mail delivery issues

jab1 — Fri, 24 Oct 2025 08:48:08 GMT

@ebforum As I read it, yes, it is the Enix server causing the slowdown.

Re: e-mail delivery issues

MisterW — Fri, 24 Oct 2025 08:50:35 GMT

@jab1

John, From my brief test this morning, I'd concur with that.

I believe its already been raised but I've added my threepennyworth...

Re: e-mail delivery issues

Townman — Fri, 24 Oct 2025 08:53:59 GMT

Objective evidence has been sent to the business, though they relate to what is clearly SPAM emails, which justifiably might be handled differently. I've sent clean communications this morning which have been delivered instantly.

Re: e-mail delivery issues

ebforum — Fri, 24 Oct 2025 09:25:54 GMT

@Townman as stated in my original post, my objective evidence is that the problem is not aligned to Spam e-mails. None of my delayed e-mails were Spam, all being authentic sources, and as stated, including e-mails from PayPal.

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

ebforum — Fri, 24 Oct 2025 10:13:38 GMT

@Townman To make it clear for those looking at this thread, I posted my delayed e-mail issues in the other thread as I thought the problem might be linked to any configuration changes Plusnet has implemented recently in respect of e-mails to Microsoft domains. Clearly after a couple of replies and further investigation it wasn't related, hence setting up this new thread.