esackbauer
Yes, of course, but if you’re sending out newsletters, for example, it doesn’t really matter ;-)
But seriously. My main point was that you can’t really know what the big mail providers are doing, it’s not like they’re particularly transparent about their anti-spam measures, for good reason, so it’s hard to say why in some cases emails don’t get through, always assuming you’ve followed all the best practices regarding mail delivery of course.
There are of course many other factors, in addition of the ones I mentioned, such as limits on free accounts, or certain providers generally blocking emails from new mail servers.
Also, If you set up a Mailcow today with a VPS provider, that lets you send email from day one, your VPS is likely on blocklists already, and if it is a more serious provider, and you have mangaed to let them allow sending email, and the first thing you do is sending a few hundred emails to icloud.com accounts, you are likely to be blacklisted immediately. If you send mail too infrequently, you will run into issues as well, as they will almost certainly do some weired version of greylisting. And there are also TLDs that are not popular, such as .xyz,
But in the end it’s all a bit of a guessing game. ;-)