Outgoing SMTP connections time out while sending e-mails to some domains.
Issue cause
Some email servers advertise support for some SMTP features that they cannot handle. This is very likely with content control gateways.
Solution
A custom Acceptance & Routing advanced rule must be defined from the webadmin interface.
To do this, log into the webmail interface and go to "Security & Filtering" -> "Acceptance & Routing" -> "Advanced Settings" tab. On the page that loads, click the "Add acceptance / Routing rule" button.
Set the name of the custom rule to something suggestive, like "Relay-Timeout". In the "Conditions" section, leave the settings as they are, for the rule to match any e-mail message. In the "Actions" section, select from the drop-down box "SSL encryption" in the "Relay" section. Click the "Add action" button. From the same drop-down box, select "Settings" -> "Allow Start TLS" and click the "Add action" button again.
You must make sure that both of the checkboxes for the added actions are un-selected for this workaround to achieve its goal. Click the "Save configuration" button at the bottom of the page to save the rule and enable it.
To do this, log into the webmail interface and go to "Security & Filtering" -> "Acceptance & Routing" -> "Advanced Settings" tab. On the page that loads, click the "Add acceptance / Routing rule" button.
Set the name of the custom rule to something suggestive, like "Relay-Timeout". In the "Conditions" section, leave the settings as they are, for the rule to match any e-mail message. In the "Actions" section, select from the drop-down box "SSL encryption" in the "Relay" section. Click the "Add action" button. From the same drop-down box, select "Settings" -> "Allow Start TLS" and click the "Add action" button again.
You must make sure that both of the checkboxes for the added actions are un-selected for this workaround to achieve its goal. Click the "Save configuration" button at the bottom of the page to save the rule and enable it.
OS:
LinuxWindowsFreeBSDNetBSDOpenBSDSolaris
Distros:
WindowsDEB based distros amd64