Looks like certain specific services always send notifications correctly and certain other services always send them incorrectly.
If some services are working and some are not, this is typically a configuration issue. What is the exact names of the hosts and services that are not sending notifications?
No, they are all working but they are coming out from email address [email protected] instead of the one in Email Settings. And those emails are going to the Internet using the MX record lookup, instead of using the internal Exchange server that is defined in Email settings.
Those emails are being sent by postfix (Sendmail) rather than PHPmailer. Can you post a screen shot of the Email Settings page?
Also, you have a few contacts configured to use the Nagios Core handlers and not XI notification commands. Specifically, AlphaSuiteSupport, Ze Wang, agrybas, alphasuitedev, asingh, hfrancisco and munter.
You'll need to configure those contacts to use the XI notification handlers so they will use the SMTP PHPMailer settings.