Hey, i'm searching for an answer for about 24 hours now and I still can't find any really useful help... The problem appears as the following: I'm running a debian server with Plesk 9.5.3 and qmail. Since a few weeks I'm not able to send mails to some particular servers (like web.de, aol.com). Hence I get failure notices like "Sorry, I wasn't able to establish an SMTP connection." But when I try to send mails to gmail.com - it works! Gmail only reports a softfail in the mail header like so: Received: from h1600XXX.?none? (DOMAIN2.TLD [XX.XXX.XX.XX]) Received-SPF: softfail (google.com: best guess record for domain of transitioning [email protected] does not designate 85.XXX.XX.XX as permitted sender) client-ip=85.XXX.XX.XX This sounds like a dns problem for me, but I can't get an answer for that... What makes me wondering is: h1600XXX is correct, but it should look like h1600XXX.stratoserver.net, not ?none? DOMAIN2.TLD (first line) is different from DOMAIN1 (second line). Both are hosted on this machine, but is this correct? DOMAIN1 is the one I send this mail from. Hopefully someone could help me! If you need more specific information, let me know. Thanks in advance!!! Best regards