Install and enable mailcatcher or mailhog or have your Moodle correctly configured to send emails or use a SMTP server Enable Messaging in Moodle advanced features Enable "Allow site-wide messaging" in the same page Create or use two existing users: u1 and u2 (with real email address if using a real SMTP server) Log-in as a u2, go to the "Messages" icon (top right), open the settings via the cog and select "You can restrict who can message you" -> My contacts only As u2, go to your Profile -> Preferences -> Notification preferences and check that for the "Message contact requests notification" fiel the column e-mail is set to On / On Log-in as u1, go to the "Messages" icon -> Contacts -> look for u1 by name, and add him as a contact Check that you receive an email for u2 indicating that u1 wants to add you as contact