Hi,
I am using debian 12.5 and I followed the instruction at
https://www.blunix.com/blog/secure-smtp-email-relay-on-debian-and-ubuntu-with-opensmtpd-instead-of-postfix.html#etc-smtpd-conf-example
So after I followed up, I stuck by starting the service. The output is a syntax error at line 7...