Re: Fwd: Undeliverable: Re: Word Wrapping Mathematical Formulas

It looks like outlook.com has forwarded it to gmail, and has overwritten 
the incoming envelope sender with the From: header domain.  For SPF to 
work the envelope sender should reflect outlook.com.  That looks like 
two errors:

1) setting envelope sender from From header;
2) not setting the envelope sender to the owner of the mail alias used 
(bounces from a redirection are the fault of the redirector, not the 
original).

I don't know if outlook.com always forwards, in which case this could 
affect anyone using it, or the user has opted for this, in which case it 
could be as little as the one user.

On the first point, although I don't know if it is still true, Microsoft 
Exchange used to be noted for sending out of office replies to the From: 
header address, which was a big nuisance for mailing lists.  I presume 
outlook.com is also Microsoft.


On 02/07/2023 19:00, Patrick H. Lauke wrote:
> *mx.google.com rejected your message to the following email addresses:*
> 
> abaskdekaboom@gmail.com <mailto:abaskdekaboom@gmail.com>
> Your message wasn't delivered because the recipient's email provider 
> rejected it.
> 
> *mx.google.com gave this error:
> This mail is unauthenticated, which poses a security risk to the sender 
> and Gmail users, and has been blocked. The sender must authenticate with 
> at least one of SPF or DKIM. For this message, DKIM checks did not pass 
> and SPF check for [splintered.co.uk] did not pass with ip: 
> [2a01:111:f400:7eab::203]. The sender should visit 
> https://support.google.com/mail/answer/81126#authentication for 
> instructions on setting up authentication. 
> i21-20020a1709061e5500b00991c8ce54c5si8580126ejj.178 - gsmtp
> *

Received on Sunday, 2 July 2023 18:41:56 UTC