Q: can no longer send mail after installing Yosemite

I am taking my MBA in to the Apple store on Friday morning.  If the issue is not resolved by then, and they fix it, I will note it on here

I have the same issue on my Imac.  Didn't have the same issue on my MBA.  It pops up every 10 seconds

I started having this issue today, and just changed the port number (through "edit SMTP server list") to 465. Apparently the options are either port 465 or 587, so if you are having issues with one of them, try the other one. It's worked for the past 10 minutes! Fingers crossed.

I tried 465; it wouldn't work and kept changing back to 587.  I didn't have SSL checked, but then checked SSL and changed to 465 and no luck.  Thanks for taking time

I screwed around for days but got it working with the following solution.

In mail preferences/advanced un-tick 'automatically detect and maintain account settings'  Do the same thing in edit SMTP.  Apple have ticked these as a default). I think I then deleted my password in 'account information' and reentered it (done so many thing I can't remember!).  My port setting is 993.  It's now been working OK for the last 3 days.

Good luck.

Hey

I unchecked automatically detect and maintain account settings.  I left the port at 587 and it worked...thanks Johns3112

Yes, and another important bit is that when you change these settings, closing the window won't save them. Instead, before closing the window, click on another account. This will force the "Save Changes" dialog to appear. Click "Save" then you may close the window.

I had the same problems, and this post fixed it for me - works flawlessly now.

Mail SMTP (outgoing) does not work after Yosemite upgrade

I had to change to port 25 for mine to work.

(outgoing that is)

I have the same problem.  I installed Yosemite more or less when it came out and all was fine until suddenly today, when I found I could no longer send emails from my Claranet IMAP account.  All my other accounts work fine, but when I try to send from this account I get an error message: 'Cannot send message using the server replay.clara.net'.  But, if I select an alternative server, the mail still doesn't go and I get the error message for the server I switched to.  This being the case, and since I have no problems sending emails from this Claranet IMAP account on my iPhone and iPad, this is clearly a Yosemite problem and not a problem with Claranet  

I have tried every solution suggested in this and other strings on the subject and none has worked.

This is a major one for me, since this is my business account.  I desperately need a fix.  PLEASE CAN APPLE ACKNOWLEDGE AND FIX THIS ISSUE ASAP?  It is way too common to ignore.

Also, the folder set up has gone crazy for this Claranet account - and only this account, so I imagine the problem must be connected.  The in-tray icon for this account - which is in the list of my 7 inbox in-trays - has an arrow against it and all the folders - sent, junk, drafts, etc - are within it.  And, within the folders for he respective sent, junk, drafts, etc sections in the sidebar, this account always has a black circle against it and no content.

Oh, and I forgot to mention, when I try to delete an email from the Claranet account within my Inbox, I get a message saying 'An error occurred while moving message to mailbox "(null)".', although the email is deleted from the inbox

What outgoing port are you using? Have you tried changing it? Have you messed around wtih my myemail.com to see if you can get some other configurations to work? How about deleting your IMAP account from Mail.app and trying it again?

ANOTHER FIX!  After accomplishing the above mentioned fixes, I still encountered occasional problems. I seem to be having luck rebooting my wireless router. It's a real hassle, but fixes the problem, ...for awhile anyway.