Hello all.
I am having an issue with the email server on my CyberPanel VPS.
- I am unable to connect via TLS/STARTTLS, with a mail client, even though I’ve installed the certificates.
- I cannot receive emails. Logs show
"Nov 17 05:25:26 ATL01 postfix/smtpd[337886]: 40491603DD: reject: DATA from outsidemailserver.tld[xx.xx.xxx.xxx]: 451 4.3.5 **Server configuration problem**; from=<chris.xxxxx@outside.tld> to=<chris.xxxx@inside.tld> proto=ESMTP helo=<mail-qt1-f182.google.com> - When trying to send email via SMTP, the mail client (thunderbird in this case) just reports a vague error and says there is a server configuration problem.
Any ideas where to begin, and what to look for?