This is another issue I see from time to time in Support Requests showing up in my team

This time the DNS settings are fine but the Appliance is still not able to send the emails, and a reboot of the appliance is not helping.

So let’s have a look at the /var/log/messages.

2018-01-15T12:44:41.259549+01:00 vcenter sendmail[35923]: w0FBifp0035923: size=535, class=0, nrcpts=1, msgid=<>, relay=root@localhost
2018-01-15T12:44:41.275104+01:00 vcenter sendmail[35923]: w0FBifp0035923:, (0/0), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30535, relay=[] [], dsn=4.0.0, stat=Deferred: Connection refused by []

OK, so we will get a Connection refused by [] when the vpxd process is trying to send the email to the local sendmail server for delivery to the relay host.

When checking for the port with netstat -tulpen | grep :25 we will get no result.

In this case, restarting the service using systemctl will not help, as there will be a conflict regarding the port.

The easiest way to fix the issue is to simply open the web client, go to the vCenter email settings and remove them, save the changes and re-add them.

This will restart the sendmail daemon using the vCenter internal way of managing system services.

Now you vCenter should send emails again.