Hello Paul,
First we need to know which emails got bounced as we can check logs on the
VPS Hosting to figure out what went wrong for those emails. Best option is to open a new ticket for our
VPS Hosting team and have them do settings as per your requirement. Also ask them to configure security settings for your
VPS Hosting as we keep high security on our shared and reseller hosting servers but each
VPS Hosting needs security settings to be implemented individually so its better to communicate with them and get some basic security settings done to avoid any kind of hacking / cracking attempt in future.