After digging around a little more and understanding more about how the NS8 email notifications are set up, I went for this:
Guess what, it still has the “auth none” which is the error condition as posted in my original report:
[root@ns8 ~]# runagent -m backuppc1 podman exec -ti backuppc-app bash
[tiredofit/backuppc:6.0.4 17:04:34 /] $ cat /etc/msmtprc
### Automatically generated on container start. See documentation on how to set!
account default
host 10.5.4.1
port 25
domain %H
maildomain %H
auth none
tls off
tls_starttls off
tls_certcheck off
[tiredofit/backuppc:6.0.4 17:04:41 /] $ exit
exit
[root@ns8 ~]#
Also will this work with the host it has, as that is the address of the Wireguard VPN interface.
Also is there a command, similar to Samba, to change the IP within BackupPC because it gets very upset if the IP of NS8 changes. Take a look here.
Cheers.