Follow the instructions in the Lotus Domino Server documentation page Configuring Domino to send mail to a relay host or firewall.
Where it is asks for Relay host for messages leaving the local Internet domain, enter the value mail.smtp2go.com.
If that doesn’t work, enter the value [220.127.116.11].
When entering an IP address as above, square brackets [ ] are part of the value, so be sure to include them.
Within the configuration document of your server (not the server document) there is a section for Router/SMTP.
Go to the Router/SMTP tab, Restrictions and controls tab, SMTP Inbound controls tab, Inbound Intended Recipients Controls section.
Set “Verify that local domain recipients exist in the Domino Directory:” to Enabled.
Note: If you see an error ‘550 unable to verify sender address’ when trying to send an email after setting up, this means your ‘From’ email address doesn’t have a valid MX record setup yet. All emails must be sent from an email address that has an MX record at its domain name.
Try SMTP2GO free for as long as you like:Try SMTP2GO Free → Paid plans available for over 1,000 emails/month.