Updating Password Authentication Method in Windows/Thunderbird
To ensure Thunderbird's settings are properly configured:
1. In Thunderbird, go to "Tools" > "Account Settings..."
2. Select the Outgoing Server category
3. Select your SMTP server. Then hit "Edit..."
4. Under "Authentication Method", change the option from "Encrypted password" to "Normal Password".
Note: Normal Password authentication will not decrease the security of email transmission as that data is being delivered over a secure SSL connection.
5. Select OK to accept your changes, then OK again to close the Account Settings dialogue.