To get a list of the Send Connector names configured in your organization, run:
Get-SendConnectorHere's the one-liner that configures a Send Connector to use port 465:
Set-SendConnector "Your SMTP Send Connector" -Port 465If you're using a Microsoft Edge server, you will need to configure this from any server that is not running the Edge role. You will also need to wait for an EdgeSync operation or force it manually:
Start-EdgeSynchronizationNo services need to be restarted for this change to go into effect.