Sending of message failed.
The message could not be sent using SMTP server mail.vjandrews.com for an unknown reason. Please verify that your SMTP server settings are correct and try again, or contact your network administrator.

Thunderbird is a great email program, but it's sometimes doesn't always accurately auto detect server settings. You will need to locate the outgoing server settings in your Thunderbird email program then call your Hosting provider to verify/correct your outgoing email setting.

Locate Outgoing Server SMTP Setting in Thunderbird

1. Open Mozilla Thunderbird.
2. Right mouse click on the email address on the left side of the application and select 'Settings'.
   
3. Click on 'Outgoing Server (SMTP)'.
   
4. Select the email address that you are unable to send from, in the list.
5. Click  the 'Edit' button.
   
6. A popup window will appear allowing you to edit your outgoing server settings. Call your hosting company now and ask them for the proper settings. They will have you input the proper settings.
7. Click the 'OK' button.
8. Click the 'OK' button again.

You should be able to send messages now without receiving the "Sending of message failed. Thunderbird' error.