Am 21.10.20 um 11:42 schrieb Gary Stainburn via Exim-users:
>
> host mx-eu.mail.am0.yahoodns.net [188.125.72.74]
> Delay reason: SMTP error from remote mail server after end of data:
> 421 [IPTS04] Messages from x.x.x.x temporarily deferred due to
> unexpected volume or user complaints - 4.16.55.1; see
> https://postmaster.verizonmedia.com/error-codes
>
> As I'm only emailing members who asked to join the group I doubt that
> they have had complaints so it must be down to the high volume.
>
Your mail provider for your company account will be whitelisted at yahoo
and others to relax rate limits for him.
Your own mailservice is not whitelistet and therefor under rate limit.
You could contact yahoo and fillout the whitelist form,
or don't send out as much mails per second as you do now. On this list
should enough examples how to rate limit yourself for a specific
external mailserver.
best regards,
Marius