[iMOTOR]

I use dreamhost IMAP for our company email. Bought a new MacBook Air for someone and setup their email account in Mail App.

She checked her Sent folder today—no messages since switching to new computer about a month ago. I tried sending a message, you get swoosh sound and no error message. The messages are not in the outbox either.

Dreamhost says no sent messages through their server since we upgraded the computer.

So about a whole month of thinking messages were going out, but not.

Why isn't Yosemite Mail App producing an error if messages aren't going out?

[ibook_steve]

You said the messages are going out, but you didn't mention if the other side is receiving the messages! If they are being received, check the Mail preferences. Under Accounts, select the account and go to Mailbox Behaviors. See if sent messages are being stored.

If messages are not being received, check the SMTP settings for the outgoing server.

You can also open the Activity window or the Connection Doctor to try to figure out what's going on.

Steve

[iMOTOR]

During the chat with dreamhost they said they have not received any of the messages that were sent out.

[besson3c]

Is it possible you are using a different SMTP server?