New instance cannot send email via Gmail

Setup a self hosted instance and am using Gmail SMTP server with an app password. However, when I try to register a test user, I get an error indicating that "This server hasn't correctly set up email."

I used the Lemmy Easy Deploy project to set my system up. Following is the relevant section of the lemmy.hjson config file:

  email: {
    smtp_server: "smtp.gmail.com:587"
    smtp_login: "<user_name>@gmail.com"
    smtp_password: "my_super_secret_password"
    smtp_from_address: " <noreply@lemmy.example.com>"
    tls_type: "tls"
  }

How can I find out why my Lemmy server thinks the email isn't setup properly?

How can I send email from my instance using a Gmail account I created for this purpose?