can not send email

Hello to all one of the users on a list that I am running is having problems sending email on mail.
He uses a bleyounder.co.uk account.
We have tried going to preferences and then going to accounts to see if all of his iMap settings are correct.
They are correct.
Then we tried deleting and reading his account and then it still didn't work.
For some reason after deleting the account in internet accounts it is deleted but in mail it is not deleted.
The next thing we did was look at the connection doctor it looked like every thing is okay.
Now he is receiving mail just fine but now for some reason he can't send email for some reason.
What could be the problem and how can we fix it.

Forum: 

Did you check the SMTP settings?

Club AppleVis Member

You mentioned checking the IMAP settings, but did you check the SMTP settings as well? SMTP is used for outgoing mail, while IMAP is used for incoming mail and to save a copy of sent mail to the mail server. If there is an issue with the SMTP preferences, you may not be able to send mail but will still receive mail.

Also, make sure Mail is configured to use that particular service for sending mail. It is possible to set up Mail to use one account for reading mail and another account for sending. I had to do this many years ago when an email account I had only let me send mail if I was logged into their network as my ISP, so if I was at home instead and needed to send email, I had to use a different email account to send mail.