topic Email Server Error 4.3.2 in Email

Email Server Error 4.3.2

Thimbles — Fri, 24 Oct 2025 09:53:14 GMT

Since last weekend all e-mails I have sent from Outlook using my Free-online domain have been bounced with the message " Server error :451 4 .3.2 Internal server error" .

I have checked my settings in Outlook, which have not changed, and used the test function which also throws up the same error for outgoing mail. I do not believe I have yet migrated to Greenby - no notification ? but is this something to do with upcoming migration?

Moderator's note:
Thread title changed to more accurately describe the problem

Re: E-mail Undeliverable

Townman — Tue, 14 Oct 2025 21:54:13 GMT

Set authentication on the SMTP server settings.

Blind copies to my own address not being delivered

ann3 — Thu, 23 Oct 2025 11:43:47 GMT

As of this morning, blind-copying my own address into important emails, for my own info, has suddenly stopped working, in the sense that the blind copies are not arriving in my in-box. I'm working in Mac Mail, but have also checked via the plusnet webmail interface, and the blind copies are not there either. They are not in spam or junk. Any ideas, anyone?

Re: Blind copies to my own address not being delivered

ann3 — Thu, 23 Oct 2025 14:23:35 GMT

Think it was a blip - it seems to have fixed itself. It just came at an extremely inconvenient moment.

Re: Blind copies to my own address not being delivered

Kwak — Thu, 23 Oct 2025 15:54:28 GMT

Definitely seems to a problem. I've had emails forwarded to plusnet for years and today (no config change) some are getting through, some aren't. So it's intermittent, like some of these problems in the past. I just had this error at 16:19.

It has given up and reported (and this seems very specific as a plusnet problem)

Technical details of the failure: 
4.3.2 All server ports are busy

and

Technical details of the failure: 
Problem communicating with the recipient server

Re: Blind copies to my own address not being delivered

Kwak — Thu, 23 Oct 2025 18:08:56 GMT

Have had a number of further reports back again from email provider that forward to my plusnet, all

Problem communicating with the recipient server

This is the sort of thing that was happening a while back, year ago maybe?

Re: Blind copies to my own address not being delivered

Townman — Fri, 24 Oct 2025 10:28:41 GMT

Can you get something more detailed from them? That phrase covers a lot of sins!

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

Kwak — Sat, 25 Oct 2025 08:13:44 GMT

As I noted in another thread I've been having problems with email that is forwarded to plusnet since yesterday as well.

Basically the forwarded gives up and emails me that it's given up. E.g. I just had "Mail Forward Failure"

Diagnostic-Code: Problem communicating with the recipient server

Yesterday I had that error a number of times and also

Diagnostic-Code: 4.3.2 All server ports are busy

It is coming via mail.enmail.co.

I've never that I know of been told anything about a migration. Some emails come through fine, some don't.

I've changed nothing.

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Cross-posting causes nugarory work and is not allowed as per Forum rules.

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

Kwak — Sat, 25 Oct 2025 08:16:09 GMT

Intermittent, 5 yesterday, 1 error today.

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Post moved. to here. Cross-posting is not allowed as per Forum rules.

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

Townman — Sat, 25 Oct 2025 09:10:30 GMT

4.3.2 errors arise where no credentials are supplied on the SMTP server configuration.