Step 1: Open Thunder Email client.
Step 2: From the Menu Bar, Click "Tools", then "Account Settings".
Step 3: You can see the Account Settings window where you can click on "Outgoing Server (SMTP)" at the bottom of the list in on the left side of the window
Step 4: Select the appropriate outgoing server and click the "Edit" button.
Step 5: Make sure "Authentication method" is set to "Normal password".
Step 6: Click "OK" to close the SMTP edit window and again on the Account Settings window.
