Imac Apple Mail Cannot Send Email

[Noviceimac]

Imac Yosemite. Unable to send mail. Connection Doctor has green dots except for SMTP and it is red, to send Mail. Error message Can not Send Message using the server Yahoo. in the message window "Yahoo Offline" see attached.
The pass word is app specific generated and.

 

[Cory Cooper]

Hello and welcome.

-Which version of OS X?
-Can you read/send mail if you login to your Yahoo! account via a web browser?
-Have you tried quitting Mail, restarting, and trying Mail again?
-Do you have the Yahoo! account setup on any other computers/mobile devices? If so, can you send from them?
-Do you have a Time Machine or other backup? If so, you could try deleting the Yahoo! account and re-adding it.

It could simply be an issue with Yahoo!'s servers, which may resolve itself.

C