Comment on A sovereign Microsoft 365 alternative: Nextcloud and IONOS join forces - Nextcloud
Appoxo@lemmy.dbzer0.com 2 weeks agoThis sounds like issues with SPF, DMARC AND DKIM.
You mean you (or your clients) send email to gmx/web recipients and they arent even received/blocked?
Have you checked if your mail server IPs are on a blacklist?
anyhow2503@lemmy.world 2 weeks ago
I wasn’t looking for technical support. You can do everything correctly and still get your mails randomly marked as spam or not delivered at all. This has happened to us, some of our customers, multiple smaller email providers as well as several municipalities (imagine blackholing government emails, what a grand idea). They don’t send sensible return headers, they might not even return your undelivered mail at all, they won’t react to any inquiries to their postmaster contact (or anywhere else really), they will blacklist entire IP blocks sometimes. The only way to sidestep any issues with them is to pay a few thousand bucks to enter their
cool kids clubcertified sender alliance, which is what the big marketing firms use to deliver mass amounts of unwanted ads unhindered through their networks.