What does No Transport provider available mean?
When trying to send mail from the Outlook or Outlook Express mail clients a message is returned stating “No transport provider available”
Check your mail relay, if you are trying to send external mail check that the IP address you are sending from is listed in the Local IP listing. “No transport provider available” is Outlook’s way of saying “500 – Mail Relay not allowed at this server”
See also FAQ Entry KB374
Keywords:SMTP, transport, sending outlook