Why do I get "lost connection with somesubdomain.snwlhostedeu.com[126.96.36.199]..."
i am trying to send E-Mails to a Domain which is using sonicwall HES as far as I can see.
But SMTP Connection fails with the following error:
"lost connection with somesubdomain.snwlhostedeu.com[188.8.131.52] while performing the HELO handshake)"
If I try to test with telnet I am getting "554 No SMTPd here...":
# telnet stl-nbg.de.snwlhostedeu.com 25 Trying 184.108.40.206... Connected to stl-nbg.de.snwlhostedeu.com. Escape character is '^]'. 220 ams0vm-hesra04.colo.sonicwall.com ESMTP snwlhostedeu.com 554 No SMTPd here 202106011956472107112;1544 Connection closed by foreign host.
I am not able to transfer E-Mails from this postfix E-Mail System to a Domain using HES.
Any Idea whats wrong here?
Is this some kind of feature of HES? Usually testing with telnet works on smtp servers and also some kind of reasonable error response like "blocked by RBL" etc. is given.
I appreciate any hint that leads me a step further.