Thunderbird won't send -- also bad type font

[Josef Lowder]

.
Just installed Thunderbird and am not able to send email. 
I can receive, but not send. As far as I can tell, all the 
account settings are correct (same as on my other computer), 
but cannot get it to send a test email. 

Also 

The text-font in the message body is way too small and a 
different font (very hard to read) than in the "To" "From" 
and "Subject" fields.  How do I make them the same? I've 
turned off HTML and tried different sets in "view" without 
success. 

I've tried searching the Thunderbird forum but can't find 
any help.