Meridix uses SendGrid as a the default SMTP provider and the following host and IP is used for outgoing mails from our hosted systems.
Host:
o1.distribution.meridix.eu
IP:
198.21.7.95
Use MX Toolbox to verify that the host/IP is not blacklisted (http://mxtoolbox.com/SuperTool.aspx?action=blacklist%3ao1.distribution.meridix.eu&run=toolpage)
Each installation can have a custom SMTP definied and a customer within an installation can also have an overridden SMTP.
The DNS includes a record for distribution.meridix.eu that points to sendgrid.net (CNAME) and is not used for sending mails (it can be blacklisted).