To factor out possible SMTP-server issues we can use Telnet to try and establish a connection to the server from the computer.
- Type Telnet into the search field in the toolbar at the bottom of your desktop.
- Click on Turn Windows features on or off. This opens a pop-up window.
- Scroll down to Telnet Client, check the box next to it and press the OK button.
- Open up Command Prompt run the prompt bellow, replacing smtp_server with the name of your server and changing 587 with the desired port:
telnet smtp_server 587