I have read this entire thread. I have tried all recommendations [except the gmail account try]. Still, I am not able to send email.
Katie, never got the new email add verified and could not delete the original email [this was not allowed]
ATT was of course no help [blaming Mail as you know].
In full disclosure, I have a MacG5 pre-intel [Dual 2 GHz PowerPC G5 using OS X 10.5.8]. I guess this may be the problem.
Thank you for trying!
I have struggled with this on and off for years. I am an AT&T/Yahoo customer and one thing that seems to have helped me somewhat is to adjust my DNS settings to explicitly specify the Yahoo DNS servers instead of relying on my router to do it. I read somewhere that this was a semi-common problem between Mac OS and some routers (like the one AT&T sold em) and some servers (like Yahoo's smtp). It's worth a shot if you're having trouble. If you're not an AT&T/Yahoo customer, I'm not sure if this would help you or not. I'd probably first try it with the DNS servers provided by your own ISP (you'd need to look them up in your router or ask your ISP), and if that didn't work maybe I'd try the Yahoo DNS servers (I have no idea if they are available to non-Yahoo customers but again it's worth a try).
To make this adjustment, go to System Preferences -> Internet & Wireless -> Network. Then select your network profile e.g. AirPort or Ethernet (or both) and click the Advanced ... button. Click on the DNS tab and then under "DNS Servers" click the + button and add the IP address of the DNS server(s) supplied by your ISP. In the case of AT&T/Yahoo, at the time of this post, I'm using:
Those addresses could change over time so you should verify them. Good luck!
I thought I'd add another possible fix to some of the issues here. My mail problem started abruptly yesterday - it may have been just after having to reset my password in my itunes account - I'm not entirely sure about the order of things as it all got fairly messed up for a bit. At any rate, I have been able to send email, but cannot receive it - only on my home computer - the mail was coming through fine on my iphone and on the cloud account. I tried the Connection Doctor advice above (very helpful, as I had two accounts not connecting). Still though I was not getting my mail on the computer.
Here's what worked for me: in mail, I went to "Mailbox" in the toolbar and then chose "Synchronize" for my account. It took a bit of time, but I let it run its course, and Voila! Fixed....for now ;-)
Best of luck, and hope this is of some help. I know I have benefitted greatly from the time you've all taken to post your advice and follow up info.
Thanks for solving my problem. I have been frustrated for months, after many hours, both telephone and online, pursuing all of the traditional 'support' resources (Apple, AT&T, Yahoo) with no one having a clue. AT&T even pushed a 'contracted - for a fee' tech company, which, also, did not have a clue. I even suspected AT&T of trying to force users into a more costly program (U-Verse). If the answer is so simple, why aren't the online support programmers enabled to supply this information? I think registering a 'class' complaint with an appropiate regulating agency might get some action!! Any ideas?
Thank you very much for your suggestion. I have been breaking my head over this issue for a couple of days now. Mac Mail using Yahoo SMTP works fine from home (Comcast), but not from work (ATT DSL).
Looking at the Connection Doctor output, I finally realized that I was hitting the wrong IPs for smtp.mail.yahoo.com. They were being resolved incorrectly by ATT DNS.
Changed to use the Yahoo DNS servers and worked like a charm. Will have to keep an eye on these servers going forward I guess, but that is a small price to pay.
MBAir MacOS 10.8.2
Mac Mail 6.2