rkennedy wrote:It still looks to be using sendmail.
Can you navigate to Admin -> Contacts -> nagiosadmin -> Alert Settings -> Click Manage Service Notification Commands, and Manage Host Notification Commands.
What commands are assigned to those two commands?
On a side note - have you had a Nagios XI quick start yet?
Service ---> xi_service_notification_handler
Host ---> xi_host_notification_handler
It was too messy.
I decided to re-configure all my Nagios XI machine, and now the Notifications are working properly.
I think anyway it was a php error.