You can modify the email configuration settings of a vCenter Server.

Connect to a vSphere server.

1

View the current email configuration settings of the vCenter Server from the $srv variable.

Get-AdvancedSetting –Entity $srv  –Name mail.*
2

Update the SMTP server name and port.

Get-AdvancedSetting –Entity $srv  –Name mail.smtp.server | Set-AdvancedSetting –Value smtp.vmware.com
Get-AdvancedSetting –Entity $srv  –Name mail.smtp.port | Set-AdvancedSetting –Value 25