How to configure an external SMTP server in Plesk – Plesk
How do I use an external SMTP server? · Issue #1617 · RainLoop/rainloop-webmail · GitHub
Opportunistic TLS Router for IIS SMTP Service/SMTP Server
How to Install and Configure SMTP Server on Windows
Use Remote SMTP Server for Email Deliveries
Setting up SMTP server for email relay - TelosHelp
The EXPTA {blog}: How to Configure an Internal SMTP Relay Server for Office 365
Remote SMTP settings cPanel
How to Install and Configure SMTP Server on Windows
Automation Server > Automation Server configuration and administration guide > Initial project configuration > Best practices in the production environment > Configuring the SMTP service through IIS