Remote-MTA: dns; relay-2.mail.demon.net (188.8.131.52)
Diagnostic-Code: smtp; 550 relay not permitted
Users connected via Outlook Web Access (OWA) also get disconnected.
Our ISP has set three MX records, one pointing to our IP address (which forwards to our Exchange server) and the other two pointing to relay-1 and relay-2, which are supposed to be backup servers at DEMON (our ISP).
We have a very slow connection (512/256 KHz), but it has always worked before.
All bounce back email shows that relay is not permitted from either of our SMTP relay servers.
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