If no verification email arrives

  1. Read the status shown in the SMTP verification window.
  2. Confirm the host, port, encryption type, username, and provider-specific password.
  3. Check the recipient inbox and spam folder.
  4. Confirm that your provider allows SMTP access from desktop applications.
  5. Check firewall, antivirus, VPN, and network rules that may block the SMTP port.

“The token supplied to the function is invalid”

On Windows this normally indicates a TLS or certificate negotiation failure. Confirm that the selected security type matches the port, update Windows root certificates, and test without TLS-inspecting antivirus or proxy software where appropriate.

Use the standalone tester

Open Verification tools → SMTP tester → Test Now to test credentials without saving a sending account.