Most notifications not sending

[mirann]

I made a fairly large change Saturday morning, around 12:30am. Since then, most notifications have stopped being sent. Scheduled reports, test emails, and about half of the checks that are based on localhost continue to send, but that's pretty much it.

Notifications that do send are visible in the logs Messages, Syslog, and Maillog.
Notifications that do not send are visible in Messages and Syslog only.
I was able to pause the Postfix queue, I was only able to see those emails that were sending.

Server has been rebooted, database repair was run and no issues were found.
We upgraded from 5.6.1 to the current 5.6.9.
We've tried both sendmail and SMTP with no change.
I've been able to use the event handler to send mail from the command line.

The change that was made was a sizable addition of service checks, but shouldn't have impacted a majority of what is no longer working. Additionally, rolling back to prior configuration isn't really an option at this point.
Please let me know any thoughts...


System
Nagios XI version: 5.6.9
XI installed from: manual
Release info: nagiosprod102 4.1.12-124.34.1.el7uek.x86_64 x86_64
Red Hat Enterprise Linux Server release 7.6 (Maipo)
Gnome is not installed

[scottwilkerson]

With the complexity of this and how much information we are going to likely need,I am going to request you open a ticket here
https://support.nagios.com/tickets/

Please include a profile.zip from Admin -> System Profile

Also, include what your current setting form email is set to (SMTP or sendmail)