This happens because our emailer adds "via yanomo.com" to the emails.
In order to solve this issue, you need to set up SPF and DKIM authentication in your DNS records. This will in essence let mail clients know that Yanomo (or rather, our SparkPost email solution) is allowed to send emails on behalf of your domain. With this verified, mail clients are more likely to treat these emails as valid and will correctly send replies to the sender instead of the primary signer.
To set up this authentication, tell your sysop or domain name provider to add the following records, with YOURDOMAIN replaced by your real domain name:
|DNS Record type||DNS Record name||DNS Record value|
|TXT||YOURDOMAIN.com||v=spf1 include:sparkpostmail.com ~all|
|TXT||scph0416._domainkey.YOURHOSTNAME.com||FIND THIS VALUE ON YOUR INVOICE SETTINGS PAGE|