How to configure MailEnable mail relaying on a Plesk for Windows server hosted on Google Cloud Platform or Microsoft Azure?
According to the official Google Cloud Platform Documentation, Google Compute Engine does not allow outbound connections on ports 25, 465, and 587.
According to official Microsoft Azure Update, Azure does not allow outbound connections on port 25.
In order to set up mail relaying, follow these steps:
Note: These services may have a free tier for some of the platform's users. For additional information, refer to the documentation of the service.
Connect to the Plesk server using RDP.
Open the MailEnable Administrator console in Start > Mail Enable.
Go to Servers > localhost > Services and Connectors > right-click on SMTP > Properties > Smart Host.
Select Smart Host Enabled and under IP/Domain specify:
In the Port field, specify 587 in case of Azure or 2525 in case of Google Cloud Platform.
Select the option The remote server requires authentication, enter the credentials provided after the registration on the mail relay service and click Apply.
Note: For more information on how to properly set up the relay authentication and proper credentials, refer to the documentation of service.
Restart SMTP Connector: right-click on SMTP > Stop and then click on Start.