o3: log error about failed email sending "postfix/smtp: to=<firstname.lastname@example.org>,status=deferred (Host or domain name not found. Name service error for name=relay.infra.opensuse.org type=AAAA Host not found"
I asked in #opensuse-admin IRC as well:
cboltz okurz[m]: I can at least recommend not to use relay.i.o.o from openqa ;-)
relay.i.o.o is (and also the nameservers knowing it) in the heroes network, which is probably not reachable from the openqa network
better use a server inside the openqa network
okurz[m] cboltz it seems this got changed, could be two years ago, maybe by tampakrap at that time. Since then it seems we have no email forwarding out of that zone