Earlier quoted context omitted.
Thanks for the details! (It's not a residential IP, it's a VM at Hetzner.) >If you don't follow the practices the industry publishes, they don't relay the traffic. They are sending us email, we forward it, Gmail throttles it because it looks like spam, and then they don't accept the bounce for example :) > I should know because I've worked in this area for quite a long time. It really is not black magick, and it is a…
If its Hetzner, they have a bad mail reputation as a result of failing to address issues with their shared resources in a timely manner. They had at one point a persistent downgrade in mail reputation to the point where it was almost impossible to keep a working mail server with them that would be accepted by any major ESP. They weren't particularly receptive to addressing support issues where their systems were brea…
MSFT sends to us but then they don't accept anything from us, not even bounces to their own mail.
Relay between gmail addresses works fine. (ARC is enabled and working for years? ... since rspamd supports it. [though it had mysterious bugs initially, so I spent quite some time with it.])
> The milter is a total pain to set up, validate, and get working.
yes :D
especially the sender rewriting one.
> High volume sending also has stringent requirements.
yep, and it makes sense! though we're nowhere near that.
thanks again for your detailed replies!