I have configured my iPhone per your instructions.  I am using TFA - and have generated an application-specific password.

 

My phone's IMAP connection is fine - I receive mail.

 

My SMTP connection shows that it is validated.

 

However, when I try to send mail it never actually sends.  No errors received, mail is not in sent folder, mail is never received by recipient.

 

I can send mail via web-mail.

 

I have re-entered the SMTP settings several times.  What else can I do?