Global smtp relay works, but not domain?

Not sure what I’m doing wrong, but cannot seem to get smtp relay to work at the domain level - though it works without issue on the global level.

That said and as this is a new installation, can anyone offer any suggestions as to what might cause this, or how I might address it?

I don’t use smtp relay so I can’t guide you but you should check whether the right conf files have been created and are using the right data:

For global smtp relay:

/etc/exim4/smtp_relay.conf

For domain smtp relay:

/etc/exim4/domains/YourDomain/smtp_relay.conf

It should work fine

Check /var/log/exim4/mainlog after you have send an email with that account / domain

I have since discovered the issue was due to HestiaCP’s requirement for domains and user accounts on the server - and that adding these to HestiaCP, then anabled me to send mail using aliases with an smtp relay as intended.