Email Alerts not sending in vCenter 6.5


  • vCenter (in my case VCSA 6.5 ) is not sending alert emails even though the mail server appears to be configured properly (in the vSphere Web Client this is on the vCenter node under Configure, Settings, General).
  • Network connectivity between vCenter and port 25 on the SMTP server is fine and has been tested.
  • The logs on the SMTP server show no evidence of emails beings sent.
  • When connecting via SSH to the vCenter Server Appliance the sendmail logs are showing errors such as:
    cat /var/log/messages | grep sendmail

    2018-07-14T04:24:46.569978+00:00 my-vc sendmail[21502]: ……: [email protected], [email protected] (0/0),
      delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30528, relay=[] [], dsn=4.0.0,
      stat=Deferred: Connection refused by []
  • Cause

    The “Connection refused by []” in the logs is the giveaway here- the settings in the client have not been applied to the sendmail service and vCenter is trying to connect to the localhost as the SMTP server.


    Go to the client and reconfigure the mail server to point at something else (it doesn’t have to be a real hostname). Then change it back to the correct settings. Normal alerts will be resumed automatically straight away.  You can test if it works by temporarily adding an additional trigger with a very low threshold to an existing alert with notification action.

    vCenter Mail Settings in vSphere Web Client

    vCenter Mail Settings in vSphere Web Client

    Thanks to vExpert Laurens van Duijin for sending me down the right path with this issue.

4 thoughts on “Email Alerts not sending in vCenter 6.5

  1. gayan

    If you are using multiple email addresses then this issue occurs when a semi-colon is used to separate each email recipient. The VMware vSphere Client user interface display each recipient value separated by a semi-colon. In the VMware vSphere Web Client, each recipient is separated by a comma. So when you are configuring email notifications for VMware vCenter Server alarms, each recipient address must be separated by a comma. Using any other delimiter may cause the notification email to fail.

  2. Michael R.

    Had this issue after upgrading our VCSA to 6.5 U2d. Actually it started to resolve the MX record for the mail address and tried to send mails over our external gateway afterwards. Your tip fixed it!

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