Re: More Sendgrid trouble?

On Thu, 8 May 2025, Michael Orlitzky wrote:

> On 2025-05-08 08:11:18, Marc wrote:
>>
>> I used a greylist where emails get a 4xx message with a link that
>> allows the email through so 'regular' users can get past it. Problem
>> is, these fucked up networks are not even notifying users about 5xx
>> and 4xx notifications.
>
> With sendgrid, it depends on the 4xx message, but they often just
> silently delete the message. It turns out that, even though the RFCs
> explicitly forbid you from doing it, this multi-billion dollar company
> has a list of hand-written regexes that they use to "parse" each
> rejection message. If the regex decides that a retry is unlikely to
> succeed, they delete it.
>
> Most interestingly, they apparently delete messages that get a
> connection refused. In the past this was easy to test: turn off your
> mail server, do something on Github, turn it back on. The
> notifications would never arrive.
>
> They're a spam company whose massive marketing department has tricked
> people into thinking they're good for sending transactional email. But
> caveat emptor, they treat your password resets and order receipts like
> spam too.

If I thought that many users had them enabled,
I would suggest requesting Mail Delivery Reports.

Perhaps I should consider enabling them.

-- 
Andrew C. Aitchison                      Kendal, UK
                    [email protected]